Designing Without A Ruler – “By Hand & Eye” Explores Designing With Dividers.

By Hand and Eye

There are a lot of design books published every year and occasionally a few get written that are actually worth buying. By Hand & Eye is one of those. It’s a book that delivers where a lot of others have gone and failed. Written in an easy, nonsense-free style, the book sets out to explain the “art” of designing with proportions rather than numbers. I’ve found that a lot of books on design tend to read more like a doctoral thesis than something that will actually explain the material in easily understandable language. By Hand & Eye succeeds because  authors Walker and Tolpin are actually practitioners of their craft rather than just writers. It’s like taking a film course from someone who’s actually made a film rather than just talk about it.

Lost Art Press is a relatively new publisher who’s books are primarily aimed at the traditional woodworking crowd but you’ll be missing out on some gems if you assume their books are only useful to furniture makers. Their books are quality products both in their content and their construction. These are not the cheap perfect-bound high-acid tomes that are the product of most publishers and will end up disintegrating on you shelves. (With that in mind, If you do happen to be a furniture and book lover, and the name Andre Roubo means anything to you, you need to must check this page out immediately.)

Jim Tolpin was the most familiar to me as I own a number of his other books, but George Walker is relatively new to the publishing world. George writes a blog called Design Matters which is a record of his journey in the search for understanding what makes for good design. He and Tolpin met several years ago and found they were both on the same path but had approached it from different directions; Walker from a preference for traditional furniture and Tolpin from a more modern bent. Both were determined to discover the “magic formula” that meant the difference between a chair or building being handsome or ugly.

What they discovered is that numbers don’t matter. In fact much of the time they just get in the way. Most of the treasured icons of furniture and architecture were made before the measured rule was in use. It was the divider that ruled rather than the inch or foot. And this system of working when far beyond architecture and furniture.

The exercises they outline are especially helpful if you have only worked on a computer as you’ll be forced to think purely about the design process without the intrusion of a ‘digital helper’. By learning to think proportionally you’ll approach design from a much less restricted footing. A lot of times computers just get in the way of good design instead of enhancing it. Once you stop using numbers and just concentrating on ratios you’ll realize you can make things much easier for yourself.

The book are also a great introduction to traditional geometry and proportion if you haven’t really studied it before or a great refresher if it’s been a while since you exchanged a mouse for a compass. They are developing a website for online access to exercises in the book and you can download some sample animations of the exercises from this web page. You can also read more about the book and download a sample chapter on this page.

While the book does concentrate on furniture design the information translates to everything else in the design world as most of the principals are found in classic architecture.

column cannon ship

For example, traditional sailing ships and cannon have a lot in common with the classical orders in that they were all based on a proportional system. This not only insured that all the moulds would be in proportion to the length of a cannon barrel but that the trunions would be sturdy enough to carry the barrels weight and that the wall thickness of the tube would handle the explosions of the powder charges. The ship’s rigging was based on a similar system. If you knew the mast length you could figure the thickness of the mast stays and the diameter of every piece of rigging on the ship, all without a calculator.

Even an entire structure could and can be built with just a stick and a piece of cordage. Take a hewn log cabin. The picture below illustrates the only drawing you need for a house. It would be scratched out in the dirt with the cord and stick using the cabin width as the main unit of measure.

cabin plan

The length is easily determined in relationship to the width, resulting in a 1.6 plan ratio. The wall height is determined as 5/8s of the width. The same length determines the diagonal roof line which results in a 3/8 rise or a 9/12 pitch. The intersections would be marked with stakes and used as a full size pattern for cutting the timbers and joints without having to use a bevel gauge or fuss with estimating angles.

By doubling the cord the lengths are easily halved into eighths. The metric system is good if you’re working with numbers, multiples of 2 are better if you are laying out a pattern with simple tools.

At one time or another you have probably struggled with a badly proportioned room without realizing it. If you have ever had to design a paneled room and find that it’s impossible to get the panel sizes to work out correctly from one wall to the next, it’s most likely because the room was designed to a bad proportion. Get the proportion of width to length wrong and period details become a nightmare.

By Hand & Eye is now available through the Lost Art Press website. You can order the book here for $34. Also, if you have a peculiar aversion to quality paper products there’s a digital edition available for $16.

Three Types Of Dividers You Should Own

Thinking that you don’t need dividers if you work on a computer is a real mistake. If you have a set of compasses, a set of proportional dividers and a set of equal-space dividers you can accomplish a lot of things in less time than it takes for you to start your computer.

Here are the three types of dividers you should have and where to find them.

Compasses / Dividers

There are a large number of compass and divider styles available. You need to find the best type to fit your work methods

There are a large number of compass and divider styles available. You need to find the best type to fit your work methods.

Dividers and compasses are both the easiest and cheapest of all three types to find and have the greatest variety. If you are just doing the exercises from the book or doing small design drawings on vellum you only need a typical compass. You don’t need to settle for a cheap office store/elementary school type, there are plenty of quality compasses available on Ebay for as little as a few dollars. Usually they will come as part of complete drafting sets, which aren’t a bad thing to own, but often you can find them as one-offs. A compass around 6″ in length should be all you need. If you are feeling like drawing something larger, you’ll need a beam compass. I own one like this which is the best I have ever found. It’s called a Feranco Beam Compass and it was made by a small firm in Cincinnati. They’re out of business but you can find them second hand. Or, you can use a metal straight edge with a set of trammel points like these.

Proportional Dividers

proportional dividers come in a number of styles, most will work for design except for the type manufactured for nautical calculations.

proportional dividers come in a number of styles, most will work for design except for the type manufactured for nautical calculations.

These are definitely more expensive than a set of dividers but are a huge time saver if you are trying to scale a drawing to a different size or want to design to a giver proportion. The cost for a set of these will run anywhere from $30 to $300 depending on the vintage and make. The pair on the left are a 1810 pair made in London. The legs are of iron which are dove-tailed into the German silver body. The tolerances are very tight on these dividers and they stay put when you set them which is often a problem with cheaper dividers. The vintage sets have points which are triangular in shape and come to a very sharp point, which they need to be. Dull points require tuning with a very fine file or emery cloth. This should be avoided if possible because the accuracy depends on the lengths of the legs being a definitive ratio to each other. The modern sets have round pins which come to a point. The advantage of this being that if the dividers are dropped the pins can be replaced, something impossible with traditional sets.

The vintage sets came in two types: standard or second quality in which the indicators ‘Lines’ and ‘Circles’ are engraved on the front, and first quality in which besides these the indicators ‘Plans’ and ‘Solids’ are engraved on the reverse side. For 2D line work you only need the first two indicators. Also, when you are looking for a used set, be sure that one of the indicators does not say ‘Speed”. These are a pair made for nautical use and won’t be very useful for our purposes.

The better quality sets had designations for solids and planes which are for volumetric calculations

The better quality sets had designations for solids and planes which are for volumetric calculations

When you set the dividers to a ratio, the difference in distance between the longer and shorter legs will mirror this. Set the ‘Line’ scale to 8 and then spread the long set of legs along a straight line. The distance between the short legs will be 1/8th the distance. The same method works with circles. Set the scale to , say 5, and them spread the long legs across the diameter of a circle. You ‘walk’ the legs around the circumference of the circle to divide it into 5 equal segments.

The '10' setting under circles gives you the ratio for the Golden Proportion.

The ’10’ setting under circles gives you the ratio for the Golden Proportion.

If you like designing to the Golden Proportion, you can set the Circle scale to ’10’ and you will have a proportion of 1.618 between the two sets of legs.

Equal Space Dividers

Equal space divider come in two sizes: 6" and 12"

Equal space divider come in two sizes: 6″ and 12″

This type of divider is the most expensive of the three, but for scaling or proportion work from drawings or photographs they are impossible to beat. These are the dividers I use the most of all I own and if I lost them I’d have to replace them immediately, despite the steep price. I bought my set decades ago for $130, new now they list for $350. Ouch. My 12″ set were handmade my Alteneder & Sons in Philadelphia and are collectors items. You may get lucky and find a pair on Ebay. New, a 12″ pair runs from $400 to $500. I’d recommend finding a second-hand pair but make sure the tips are not bent or the accuracy will be nil. These dividers are sometimes referred to as 10-space or 11-point dividers. Check the Ebay sites in Britain and Canada. I’ve seen them show up there as well.

DSC_0044

With these dividers you can very quickly divide a space into as many as 10 units. I used to use them mainly for laying out stairs or room paneling but now they are irreplaceable for scaling off a photograph or drawing while simultaneously drafting on the computer. Trying to scale the material from the computer screen while doing this would be much slower. For the times I do have an image in digital form and need to scale from the screen, I’ll flip a piece of acetate over the monitor to keep the sharp teeth from scratching the screen. It’s fun to watch people with expensive monitors see me do this and gasp in horror.

Rendering In Sketchup

For those of you who work in Sketchup and are new to rendering, or are confused by all the different rendering software packages available, a new book is coming out March 25 that will help. Daniel Tal, landscape architect and author of Sketchup For Site Design, has written a new book, Rendering In Sketchup, which is now available for pre-order or as a digital download.

rendering in sketchup

There are now a number of rendering programs on the market for use with Sketchup, with a majority of them working from within Sketchup without having to exit the program. This can be a plus or a minus depending on how you work. Even though most of the programs offer free-use trial periods of their software, It can be pretty difficult and time-consuming to decide which is  the best one for your workflow and budget.

Daniel is an excellent teacher and has written a very thorough and detailed book on the process of rendering from Sketchup using a variety of software programs as well as explaining post-rendering work with Photoshop. While not every rendering engine is covered, he does go into a great amount of detail explaining not only the basics of rendering, but his own methods using Shaderlight, SU Podium and Twilight Render.

The book covers workflow, hardware requirements, how to model efficiently for renders, use and teaching of textures and a lot more. At over 600 pages, the book is both a reference and a guide and can be read for pertinent chapters rather than just cover to cover.

You can get more information on the book here, and you can view the videos on Daniel’s Youtube site here

Here is a really good tutorial by Daniel you should watch which is based on the material from his book:

Land8 Webinar: Rendering in SketchUp – Daniel Tal from Land8.com on Vimeo.

If you want to know all of your rendering engine options, here is a list of rendering programs that work with or within Sketchup;   ( Prices are as of March, 2013. )

From within Sketchup:

Shaderlight – $299 full license; timed access from $50

Twilight Render – $99

V-Ray – $800

ArielVision – $175

Bloom Unit – free software , cloud-based, priced per render

Caravaggio – $295

Indigo Renderer – $220

IRender nXt – $499

Light Up – $189

LumenRT – $295

Maxwell – $995

Raylectron – $99

Render[in] – $160

Renditioner –  $99,  Pro $199

SU Podium – $198

Thea Render – $420

Standalone Software

Artlantis

Kerkythea – free

Understanding Model Scales – A Comparison Study

Comparative Scale Figure Diagram – You can download a pdf copy of this diagram below.

Even with the large number of computer 3D modeling programs available to designers, there is  (and I think always will be)  a place for physical scale models. Although the modeling programs continue to produce more and more realistic looking images, they are still only a 2D image that utilizes correct perspective. And even the programs or systems that are ‘true 3D’ are really only offset 2D images meant to trick the mind into thinking it’s seeing a dimensional physical shape.

Some of the advantages of a physical scale model are:

-The physical size of a set are much easier to grasp than from a digital model where you can zoom in endlessly.  I once built a model of an area of geography that the producers couldn’t seen to understand exactly how big an area it was until I put in the final piece, a model of the 260 foot ship they planned to use for a crew base. The huge ship measured only 3/16″ in the model scale. They got it instantly.

-A number of people are able to simultaneously view the model and discuss it. A lot of revelations often come from being able to look at a model from many different angles at once.

-The brain isn’t spending effort trying to do the mental tricks required to process fake 3D images. The model is somehow “more real”, because it is.

The Diagrams

I created the chart above as well as the list below from many years worth of notes and scribbles. The calculations are mine so any mistakes are solely mine as well. The visual chart will give you an easy way of determining the size of figures in the various scales that will be most common to concept models.

The list describes what I think are the most useful model sizes  from 1:700 to 1:6 with inch equivalents for each scale as well as the length of a linear foot and meter for each as well. The last column gives the common uses for the scale to help you determine what products exists for purchase. The Size Chart also lists the most common Imperial and metric drawing scales so you can find the model sizes that most closely match.

Download the full list below.

Determining The Size Of Your Model

Your first calculation will probably be how large the overall model needs to be. You’ll want the model to be as detailed as possible but probably won’t want it to take up and entire room. Using the Size Chart, multiply the overall actual size of the area you need to cover by the foot or meter equivalents and then determine which scale is best for the space you have available. Also note that 1/32 and 1:32 refer to the same scale.

Next, determine what model items exist in that scale. For the most variety in objects and vehicles, stick with the train gauge scales. If you need a lot of detailed plastic trucks or cars, 1/24th scale is going to probably be best, which is also the same as 1/2″ to the foot and is close to the German “G” train gauge.

Download The Files Here

Comparative Scale Figure Diagram

When you print this diagram, be sure that you print it at 100%. Check the inch and metric scales to be sure it is at full size for an accurate representation.

Scale Model Size Chart

Other Articles

For more information, you can refer to the following articles:

List Of Scale Model Sizes

Combining Figures With Models

Converting Scale Ratios

Finding The Right Scale For Your Model

P.S. – Your Rendering Software Is Obsolete

An article at PC Magazine.com last November talked about how real-time rendering is changing the movies, mainly in terms of how it affects the workflow and the time involved in creating animated films. Because of the advances in processor speeds and the continuing evolution of software programming, animators are beginning to be able to animate in real time. The giant rendering farms of the Far East may soon be a thing of the past.

Creating renders, at least for me, is a tedious affair that ends up eating hours of time while processing images, and renders ( pun intended ) my computer a slave to the rendering engine, useless for working on anything else.

The new wave in rendering software is for real-time execution with full motion and lighting effects as well as physical atmospheric effects like water, fog, etc.

While not cheap, there are a number of real-time, full motion options that cut the normal still-image render time from hours to seconds.

LumenRT

The least expensive option I’m aware of is LumenRT. This is a real-time rendering engine designed for use with Sketchup, but is currently being developed for use with other modeling software. Unlike the other programs I’ll discuss, there is a calculation process involved that does take more time but the advantage of this is that you can output what is called a LiveCube, which is an executable file you can send to anyone that they can navigate in and explore the model without the need for any software. Pretty neat. The downside is that once this is done, if you make any changes you need to recompute everything.

The program boast very accurate lighting and reflection effects and this affects the render speed. The company’s site advises that you may experience slower processing speeds if your model exceeds 40,000 square feet or 500,000 polys.

Normally price at $295, the program is currently on sale for $195 at their site. You can watch a promo film below, and read a review of it here.

 

 

Lumion

The next option is a program called Lumion, which was designed based on the object-oriented analysis approach of Quest 3D, a virtual reality program designed for 3D fly-throughs and simulations.

Lumion’s interface

Lumion is a true real-time rendering engine that can import nearly any 3D model. Instead of using ray-tracing technology like most other renderers, it uses a system more like those found in gaming systems to simulate light effects. This would seem to suggest that the specular effects and reflections are not accurate but a viewing of several sample videos of the product seems to suggest otherwise. Because of the way the program operates, objects in the background are rendered at lesser resolutions meaning it can handle models with millions of polys without bogging down.

The program is touted as having a short learning curve and is able to generate full motion renders in a fraction of the time it once took to do them in programs like Maya.

Lumion isn’t cheap by any means. The price of the basic program is about $1,900 with the pro version running about $3,700. There is a free version, which is limited and there is a trial version as well. It also runs only on the Windows operating system. Check out the amazing promo videos below and read the reviews here and here.

Lumion quick overview from Lumion on Vimeo.

Waterfall Lumion techpreview from Lumion on Vimeo.

Lumion demonstration from Lumion on Vimeo.

Twinmotion 2

Twinmotion 2 bills itself as “the render killer”. It was developed by an architectural film as an in-house application but was made available to the public. Like Lumion it is capable of handling huge models because of its Level Of Detail technology that renders distant objects with less detail and increases the poly count as you move closer to them.

Twinmotion 2 interface

Twinmotion seems to have more accurate geo-locating controls as well as sun controls, but Lumion is constantly changing so that may no longer be the case. Twinmotion does create excellent renders as seen below in this side-by-side comparison of a render to actual film of the location.

At $2900, Twinmotion 2 is in the same range as Lumion. Plus, there is a $850 annual subscription fee, similar to Revit. It’s hardly a purchase one could take lightly.

So what does this mean for the Art Department? Do we need full-motion renders? Considering that renders are becoming more and more common at each step of the design process, creating full-motion renders that can be done in a fraction of the time of traditional renders might become the norm.

Maybe that’s not such a bad thing. Maybe they could provide a good transistion step into the pre-viz process. Or maybe they’ll bring some of the pre-viz work back into the Art Department.

What do you think?

Measuring Heights Without A Tape Measure

No, it doesn’t involve Google Earth or Sketchup. That was covered in an earlier post. Here are three high-tech to no-tech ways to calculate the height of a building or tree or pole or anything else you need to know the size of but can’t determine with a tape measure.

1. Theodolite Pro

Theodolite Pro is an app for the iPhone, iPod Touch and the iPad.  Made by Hunter Research & Technology , it’s a multi-function augmented-reality app that combines a compass, GPS, digital map, zoom camera, rangefinder, and two-axis inclinometer. Theodolite overlays real time information about position, altitude, bearing, range, and inclination on the iPhone’s live camera image, like an electronic viewfinder.

At $3.99, it’s worth more than 4 times the price.

Theodolite Pro screen

The apps screen data gives you your position in either latitude and longitude or UTM units, as well as the time and date and your elevation. On each side are the horizontal and vertical indicators in tenths of a degree. The device has a one-button calibration function as well as a 2x and 4x magnification for pin-pointing a particular object. There are several options for the center crosshairs, one of them are a pair of multicolored floating boxes which merge and turn white when you are plumb in both directions.

You’ll get a much better result if you mount the device on a tripod. For an iPhone, the method I like is with a Snap Mount. It has 1/4″ female sockets for mounting in either a vertical or horizontal direction.

Snap Mount device for the iPhone 4

Once the phone is mounted, you point the center at the top of the object and push the “A” buttton to take a reading. Then tilt the device toward the bottom of the object and take  the “B” reading.

Then the app will ask you for your distance to the object. The more accurate your answer the more accurate the result will be. So, you’ll either have to pace off your position or measure the distance with a reel tape or laser measure device.

If this isn’t possible, you can use the option to determine the distance and height, although this will probably not be as accurate.

There is also an optical rangefinder built into the view screen that works by way of a series of concentric circles in either size factors or mils, that you can use to determine distance if you already know the size of an object in the foreground.

optical rangefinder rings

This app has been a best-selling navigational app for some time and has become a very useful tool in many different fields. You’ll find it’s very useful when doing field surveys and it’s certainly a lot cheaper than an analog theodolite.

2.  Clinometer

A clinometer, or inclinometer is a device which measures the angle of slope and uses basic trigonometry for estimating height. My clinometer is a combination clinometer and optical compass made by the Finnish company Suunto and is called the Suunto Tandem. Like the iPhone, you’ll get better results if it’s mounted to a tripod and the Suunto has a 1/4″ socket for this.

The Suunto Tandem

You look through the peep sight, leaving both eyes open. The graduated scale is superimposed over the object you’re centered on and you can read the results as either a percentage of slope or degrees of elevation.

You sight the top of the object in the device and read out the angle. Then you refer to the cosine table on the back of the device. From there it’s just a simple trig calculation. Adding the height from the ground to the center of the clinometer will give you a very close figure for the objects height. Like before you need to know your distance from the object you’re measuring, so it would be a good idea to determine your average stride to have a semi-accurate way of pacing off distance when surveying.

The back of the Tandem has tables of cosines and cotangents printed on it to make calculations easy.

The list price of the Tandem isn’t cheap, but I’ve seen them go for $20 on Ebay, so you should check there before you buy a new one. The results may not be quite as accurate as with the Theodolite app, but you’ll never have to worry about a dead battery and the device will still work perfectly 50 years from now. Like the Theodolite app, it’s good for shooting grades and taking elevation surveys as well.

A handy addition to both the above devices is to get a Keson Pocket Rod. It’s a collapsable surveyors stadia that rolls into it’s case. It has black and white graduated scales on one side and red and white on the other. It’s a great tool to have to put in location survey photographs as well for accurately scaling details from photos when you don’t have time to measure everything at a location. They come in both Imperial and metric units.

Keson Pocket Rod

3.  Biltmore Stick

This is the cheapest and easiest method of determining height but it’s also the least accurate. This is a trick I learned from my Boy Scout days. It’s based on the Biltmore Cruiser stick which is a way of determining the heights and widths of trees and how much lumber they would yield. The Biltmore Stick ( sometimes called a hypsometer ) gets it’s name from the famed Biltmore Estate in Asheville, North Carolina and was invented in the 1890’s by a German forester named Carl Schenk who was the master forester at the estate.

A real Biltmore stick has graduated markings that take into account for foreshortening but there’s a less expensive method. We were taught to use a yard stick (not very compact) or a 6 foot folding rule, which is a little wobbly to hold vertically. I like to use a Four Fold rule which is the original folding rule from the mid 19th century. They were sometimes called Blindman’s rules because the numbers are large and easy to read, making them perfect for this use. Garrett Wade carries a good reproduction of them. They fold down to just 9 inches long and fit nicely in a survey bag.

The way to use this one is to pace off 25 feet from the tree, building, etc. Turn and face it, holding the rule at arm’s length. 25 inches from your eye is the ideal distance. hold the rule so that the bottom of it lines up with the bottom of the object, like so:

using the Four Fold rule as a Biltmore stick

Read off the number than lines up with the top of the object and that will give you the height in feet. If the object is above the 25 inch mark, back up another 25 feet and multiply the results by 2. If it is still above the 25 inch mark, back up to 75 feet away and multiply the results by 3, and so on.

This method won’t necessarily give you a really accurate height, but it will give you a number that will be pretty close, say within 3% to 4% of the true measurement, providing you are very close in the distance increment and the rule is very close to 25 inches from your eye.


Sculpting Tools For Sketchup

Most people think of Sketchup as a program that just draws boxes. As a poly-modeler it was always handicapped when it came to modeling compound curved surfaces and even with the built-in Sandbox tools, drawing terrain was never truly easy.

Now there are two different plugins that make not only terrain construction but organic and vehicle construction possible without having the urge to jump out the nearest window. I use both regularly and because they each have different attributes, I think their capabilities really complement each other when you are constructing complex shapes.

Artisan

The first is a plugin called Artisan which is a great solution for creating organic shapes. Created by Dale Martens, who has produced numerous other free plugins including Subdivide & Smooth, has created a set of sculpting tools that work very much like the sculpting tools in Maya and are incredibly easy to learn and use. The site has nice tutorial videos as well as a nice gallery of others work using the plugin. You have a series of settings which allows to to adjust the pressure of the brush, either positive or negative, and after setting the width of the ‘brush’, you drag it over the area to create the sculpted surface. The demo video below will give you an idea of the process.

One of the tools that alone is worth the $39 cost, is a poly-reducer which is a huge help when you import models from a NERB software package like Rhino or Maya. The tool allows you to select how much you want to reduce the poly count of a model to get it down to the size you need. You can also reverse the process and take a low-poly model and increase the detail.

I consider this plugin to be an absolute must for people who want to be able to build anything besides flat walls in Sketchup. Here are some examples of Sketchup models created using Artisan:

scooter by Pete Stoppel using Artisan

Motorbikes by Pete Stoppel

creature by Erik Lay

terrain by Pete Stoppel

Vertex Tools

The other plugin is called Vertex ToolsThis program has tools which work differently than Artisan but has some advantages over it in the way the selection tools work. Designed by Thom Thomassen, a modelmaker from Norway who has also designed an incredible number of other useful free plugins, has designed a set of tools that are what the Sandbox Tools aspire to be.  At $20 it, like Artisan, is a real bargain. The video below will give you a quick overview.

The selection tools allow you to set how the tool affects the surrounding polys with either a linear or cosine fall-off. This one is really a must when you are creating terrain.

At a total cost of $59 dollars, these plugins will give you a huge boost in your modeling capabilities. If you use Sketchup, they should be your next purchase. You won’t be sorry.

Would you like your metrics hard or soft?

Our team is getting smaller and smaller. The Imperial scale team, that is. Right now only the U.S. and Burma still use the Imperial system of measure. Even the British and Canadians have abandoned the system for metric units of measure.  Most countries use a system known as “S.I.” or, System International. Dimensions on drawings are expressed as millimeters, usually without a suffix ( mm ) after them.

With more and more films being made abroad it’s becoming more common for set designers and art directors to have to create construction documents that will be built out of the country. The easiest method is simply to draw in metric from the start and avoid some inevitably strange conversion numbers. Two other methods are the “soft” and “hard” conversions.

In soft metric, you draw and dimension in Imperial and then also give the equivalent metric measurement rounded to the nearest millimeter. In hard metric you dimension in Imperial and then covert to “hard” or non-rounded numbers, meaning you’re going to end up with numbers in tenths of millimeters, which is fine if you’re drawing machined parts. Since a millimeter is less than 1/32″ in length, you won’t be very popular among the people building from your drawings.

Drawing in metric straight from the start is the better way to go once you have some basic metric visualization skills. Here’s a quick list of common sizes converted to soft metric:

1″ = 25 mm

1′-0″ = 305 mm

6′ = 1829 mm

10′ = 3048 mm

Typical door height –  2033 mm  ( 6′-8″ )

Table height – 762 mm  ( 30″ )

Counter height – 915 mm  ( 36″ )

Common Drawing Scales

Here’s a list of metric scales and their closest Imperial scale equivalent:

1:1 (Full Size)

1:2 (Half Size)

1:5  (3″= 1′-0″)

1:10  (1 1/2″=1′-0″)

1:20  (3/4″=1′-0″)

1:25  (1/2″=1′-0″)

1:50  (1/4″=1′-0″)  actual equivalent – 1″= 4.17′

1:100  (1/8″=1′-0″)  actual equivalent – 1″= 8.33′

1:200  (1/16″=1′-0″)  actual equivalent – 1″ = 16.66′

1:250  (1″=20′-0″)

1:500  (1″=40′-0″)

1:1000  (1″=80′-0″)

Conversion Scales

There used to be a company in Philadelphia called T. Alteneder & Sons which made custom drawing scales. I ordered a metric / imperial set nearly 14 years ago and they’re very handy. If you can get your hands on a set, buy them.

Since there doesn’t seem to a source to buy them anymore, I made up a paper scale set for 1/4″ / 1:50 that you can print out and make yourself. You’ll need a 1 1/2″ wide by 17″ long piece of matt board or thin basswood. Download and print out the PDF from the link below on 11 x 17 paper. Be sure to print it at 100% and make sure the “zoom to fit” box is unchecked. Check for print accuracy using the “Imperial” scale. It should measure a true  1/4″ to the foot. You’ll notice that the foot increments on the blue “Metric” scale measure slightly less that 1/4″ so don’t be thrown off by them. Carefully cut out the scales and mount on either side of the board.

When working with a 1/4″ drawing, use the side with the yellow box marked “Imperial”. The opposite edge of the scale will read out equivalent metric lengths. Use the other side when working with 1:50 metric drawings and the ‘feet’ scale will give you the equivalent distance in imperial units.

Metric_Imperial_ConversionScales


					

Lens Focal Length Comparison Chart

I created this chart last year for an article in September’s Perspective Magazine. Since then I’ve been asked for it several times and decided I should just post it where it’s easily accessible.

Using a straightedge, his chart will allow you to find the comparable focal lengths of lenses available in many of the popular digital sensor sizes as well as the typical film formats. You can download the PDF by clicking the link below.

Lens Focal Length Comparison Chart