Calculating Reflections – No Computer Required

It doesn’t happen often, but you occasionally have to calculate reflections.  A scene will be staged in a way that the camera is seeing the action in a mirror and it’s immediately clear that the shot will determine how the set is staged and dressing placed.

On one production I was asked how long it would take me to render a digital model with true reflections so they could determine whether the character would be able to see the other person from where he was seated.

I told them it would probably take about  an hour to texture the model and do the render they wanted, or I could figure it out with a pencil and it would only take about 2 minutes. They thought I was kidding.

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You’ll want to have the plan view and an elevation. Line them up so that the plane of the mirror is along an identical line. It doesn’t have to be in any certain scale as long as they are both the same size. It can be a printout or just a quick drawing on grid paper, as long as the mirror is correctly placed and sized.

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Cover the drawing with trace, being sure to extend it twice as far over the line of the mirror plane.

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Now draw lines from the vantage point through the edges of the mirror on both the plan and elevation.

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Draw a heavy vertical line through the mirror plane. Then fold the trace along this line.

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Since the angle of reflection is equal to the angle of incidence, the reflected view is easily seen once the trace is folded back over the drawing, and it’s clear the person in the chair would have no way to see the person standing at the door.

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You can now pivot the ‘mirror plane’ down until the person is in view, although it will be clear that in plan the mirror would be at a strange angle from the wall.

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3 Methods Of Scaling From Photographs

 

photo-6In February I posted an article about using your hand in photographs as a scale reference but didn’t go into how you extract that information once you have a copy of your photos. Here are three methods, two analog and one digital, that you can use to figure out hard dimensions from objects in photos.

Equal Space Dividers

Once you have had some practice, this is the fastest method of the three, even faster that the digital method and you can use them right off a photo from a book or even a smart table screen. If you don’t have a set of equal dividers, also called 10 point dividers, you can buy a new pair for between $250 and $300 from various sites such as this one, or this one . They sometimes show up on Ebay but plan to pay around $75 to $100 for a used set.

In this photo of a 1840’s Greek revival casing, we’ll scale the actual size using the hand in the photo as a reference nomen.

IMG_6890The first thing you’ll want to do is draw lines outlining the sides and edges of the moulding details, then you’ll draw a centerline through your scale, whether it’s a hand or tape measure. Then draw a line parallel to this at the top of the picture crossing the outlines. Now continue the lines perpendicular to this new datum line so that they are parallel which eliminates the perspective/foreshortening effect of the photo. Then mark a known distance on the original centerline, in this case it’s the distance from the tip of the middle finger to the end crease which is 3 3/4″.

IMG_6886Now transfer these two points to the new datum line at the top of the photo. With the dividers, open them along this datum line allowing the distance between each point to equal 1/2″. They can represent any distance you want them to, but 1/2″ works best for this example. This means that 7 1/2 spaces will equal 3 3/4″ scale inches along the new datum.

 

IMG_6887Once you have these marks set, carefully move down to the bottom of the page and mark the distance at the first and last point. As each space represents 1/2″, the distance over the width of the dividers is a scale 5″ along the nomen line. For accuracy you’ll want to continuously check the spacing of the dividers against this ‘master’ to be sure you haven’t changed the setting. Most dividers are manufactured with fairly ‘tight’ joints but you can easily bump them while you’re working and throw off the setting.

 

IMG_6891Now we have a scale to measure the spacing between each of the line extensions above the top nomen line. You can mark the distance at the middle point and reduce the spacing of the dividers to equal 1/4″ in scale and so forth. I came up with an 8″ width, which when I checked the casing with an actual measuring tape, found it to be in reality 7 7/8″ to 7 15/16″. Not bad, well within the accuracy of most applications.

 

Digital Calipers

mutoh digital calipersThis method is not only more accurate than the equal space dividers but is a cheaper method as well, just not as fast at first. I have a set of Mitutoyo digital calipers which run about $180, but you don’t need anything that accurate. You’re going to be dealing with nothing finer than a thou of an inch and even that’s pushing it. A $12 pair like these are more than adequate, in fact this $9 cheap plastic pair are even better as the sharp points on the jaws of the better calipers will rip the crap out of the surface of the page of a book or the emulsion of an enlargement. They’re a lot safer to use when you’re scaling off a computer screen as well! They all have the ability to be set for decimal inches or metric.

IMG_7157The nomen in this photo is a Keson Pocket Rod, a retractable builder’s survey pole, ( don’t know if it comes in a metric version) if you don’t have one, get one right now. You’ll wonder how you got by without it. With a graduated scale in the photo it’s easy to find a correct scale. Turn the calipers on, squeeze the jaws together and zero out the reading. then you just set the jaws between a one foot increment and record the reading.

IMG_7158In this example 1 foot equals 2.665 inches. Divide this number by 12 and you come up with .222 inches equaling 1″ in the photo. Record these numbers for reference at the top of the photo. Remember that this equivalent will only be accurate over the whole area of the photo if you have been careful to make sure your camera was perpendicular to your subject matter.

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I could go into allowing for foreshortening and lens distortion calculations but that would take an entire chapter of a book.

 

 

 

 

IMG_7161There are other options to the survey pole or tape measure. Richard Mays introduced me to graduated adhesive tape on a movie several years ago and it’s a great tool. You can put several pieces within the frame and you’ll quickly see if you have  foreshortening issues. Art Director Jim Wallis has provided a manufacturer and source for ordering some for your kit. Or this one, Or this source for both imperial and metric with story pole writing space.

Photo Scaling With Sketchup

I know there are a number of ways to scale from photos digitally but if you pla
n to do any 3D modeling with them, Sketchup is a good place to start.Screen Shot 2015-04-09 at 4.36.35 PM

In Sketchup you’ll create a horizontal face and import your photo using file/import. Be sure to import the image as a texture. Stretch the image to fill the face and click. The image will tile itself over the face, so just trim  the excess repeated images.

 

Create a Group and double-click to open it for editing. This is an especially important stepScreen Shot 2015-04-09 at 4.38.50 PM if you already have other object or images in your model file. With the Pencil tool you’ll draw a line along your nomen marking out a specific distance, in this case 12″. the longer the line the more accurate your scaling will be.

 

 

With the ruler tool, measure this line from one end to the other. Ignore what it tells you theScreen Shot 2015-04-09 at 4.38.50 PM length is. Type the length you want it to be which will appear in the Value Control Box in the lower right corner of the window. When you hit return , a box will appear asking you if you want to resize the object. Click ‘Yes’ and the object will shrink/grow to the correct size and your photo image will now be at full size scale.

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Now you can trace any area you like and the tape tool will give you a correct length, Screen Shot 2015-04-09 at 4.42.54 PMproviding you are measuring in the same focal plane as the nomen. Obviously if you are measuring something in the foreground or background the measurement will be off, which is why you need lots of survey photos  if your subject is complicated,

 

 

–  R.D. Wilkins

 

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The Measuring Tool At The End Of Your Arm

I like photographing architectural details. But they’re only really useful if I have a scale in the photo. Measurements written down in a journal somewhere are bound to get separated or lost and the photo won’t do me much good if I want to replicate the detail. I rarely carry a tape measure with me all the time and usually carry a small paper ruler in my wallet, but that often gets lost of left behind.

When those times occur where I need a scale in the photo, i just use my hand. It’s handy because it’s always with me, I know how big it is and I can always refer to it later when I’m scaling the photo. It’s my built-in story-stick.hand photos_1

The hand has been a measuring device for thousands of years and is still used as a measure of the height of  horses in the U.S. and UK. The hand’s width was standardized at 4 inches by Henry VIII in the 16th century, the hand’s breadth, (just across the 4 fingers) at 3 inches, making the average finger width 3/4″.

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The first joint or distal phalanx makes a handy scale for small details as well.

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And don’t forget your shoe makes a good scale object too.

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So what do you do with these? How do you translate these into working documents? Next time I’ll explain the basics of scaling from photos using dividers.

But in the mean time, this video by writer and woodworking instructor Jim Tolpin and animator Andrea Love gives a great intro into designing with hand and body proportions.

 

 

For more on proportional design, get Jim and George Walker‘s book, By Hand & Eye from Lost Art Press. George also writes a great blog on design you can find here.

And if you want some hands-on help, Jim will be teaching a class based on By Hand & Eye at the Port Townsend School Of Woodworking on March 21-22.

-Randall Wilkins

Painted Backings – Part II

A scenic lays out a backing at Ealing Studios in London in 1939 for the film "Young Man's Fancy". National Media Museum

A scenic lays out a backing at Ealing Studios in London in 1939 for the film “Young Man’s Fancy”. National Media Museum

In my last post on painted backings I mentioned that they had some definite advantages over photographic backings but I didn’t go into details.

Here’s some of the things they have in their favor:

1. “Softness” – Painted backings have a much more atmospheric feel to them visually. This could be enhanced by adding a “haze” to the canvas or hanging bobbinette, white or black, in front of them to soften them further. Many cinematographers hated the photographic backings when they were introduced because they were too sharp, which made it hard to try and have believable depth-of-field with a backing that was supposed to imply a distant object.

2. Canvas backings can be enhance with elements to simulate a more realistic setting: L.E.D. or miniature bulbs, cellophane strips that simulate light reflecting off water features, etc. You could do that to a Translite but it’s hard to repair the holes you’ll make in it.

3. Painted backings can be altered easily to reflect changing seasons. You can paint over a backing to create, snow, leaves, remove architectural elements and restore it back to it’s original form where you would need entirely different photographic backings in each case.

4. A painted backing has infinite possibilities, any angle, and location. There’s no need to have to get a camera at the point of view you want the scene to be shot from. No need to worry you’ll get strange perspective lines from a Photoshopped image.

And for those who don’t believe a painted backing could ever look as realistic as a photographic one, I’ll offer up this little story:

Years ago I was working on a feature that involve a 160′ long backing of a coastline and ocean view. It had to match a location which was a modern house with floor to ceiling glass panels. The designer suggested a painted backing would be better for many reasons.

One of the producers scoffed at the idea saying that since we would see so much of the backing he couldn’t believe it would look realistic enough. Because the painted backing was actually going to be cheaper he was overruled on the decision. He would walk on to the stage sometimes while it was being painted and just shake his head. “They’ll be sorry”, he said.

Several weeks later he walked into the Art Department with the writer and walked up to my drafting board, pointing to a photo on the wall of an ocean view, the sun glowed in the background and the light was glinting off the water.

“You see that. That’s what they’re trying to recreate with a painted backing!” he laughed.

I interrupted him. “That is the painted backing. I shot that yesterday after they hung and lit it.” I pointed out a studio light hanging just inside the top of the frame.

He got quiet and leaned in closer, studied the photo, and then just turned and left. He never mentioned it again.

Remember, it doesn’t matter what scenery looks like to your eye. It’s all about how the camera see it.

A painted backing seen outside the set windows

A painted backing seen outside the set windows

Here are some more photos from the JC Backings / ADG event:

Brigadoon

Backing from the film Brigadoon

Backing from the original Battlestar Gallactica TV show

Backing from the original Battlestar Gallactica TV show

Painted Backings – Film’s Best Kept Secret

“In 1903, Pathé (the first Pathé studio in Vincennes) had two cameramen [who were] paid 55 francs a week. The designers/painters, much better paid, began at 90 francs a week. A week then was 60 hours and payment was made every Saturday in gold.”

Gaston Dusmenil, Bulletin de l’ A.F.I.T.E.C., no. 16  (1967)

“The scenery [ in early 1900‘s France ] was painted flat, like stage scenery. The canvas (about 20 x 30 feet) was tacked to the floor, and after applying a coat of glue size and whiting, the designer drew the design in charcoal. For complicated architectural sets a small sketch was made and squared for enlargement. Since the size paint was used hot, a scale of grays running from black to white was prepared in advance in small flameproof buckets. The scene painter worked standing, walking on the canvas (in rope shoes or socks) and using very long-handles brushes: straight lines were drawn with the aid of a long flat ruler, similarly attached to a handle. To judge the whole, in order to accentuate effects if needed or to remove unnecessary details, the artist had to mount a ladder. The completed canvases were attached either to wooden frames to form flats, or else, to vertical poles so they could be rolled up.”

Léon Barsacq, Caligari’s Cabinet and Other Grand Illusions

Mèliés' Montreuil Studio

Mèliés’ Montreuil Studio

Painted backings have been a staple of filmwork since the very beginning. Georges Méliès was the first to recognixe the possiblilites of incorporating painted backings in his films which he realized could be a vehicle for creating a dramatic narrative and not just for recording real-life as the first short films had.

Even today, with the current trend of green screens and digital effects, audiences are often unaware that the view outside the windows of a set are actually hand-painted backings. While photographic backings, basically photographic images greatly enlarged and printed on heavy mylar or polyester fabric, are the norm in backings these days, the painted backing still has not only a definite place but even distinct advantages over their photographic competitor.

J. C. Backings, who make their home in the historic Scenic Painting Building on the old MGM lot in Culver City (now Sony Studio) recently hosted a Historic Backings event along with the Art Directors Guild here in Los Angeles. They pulled a number of backings from their collection of over 5000 backings, along with several from the Warner Bros. collection and displayed them on the six paint frames where the backings were painted originally.

The storage racks for backings at J.C. Backings

The storage racks for backings at J.C. Backings

Along with the backings were displayed a collection of smaller scale studies, paint notes, research photographs and examples of the backing design process as well as numerous photos of backings from their archives.

Usually only seen in partial focus and in the background, it’s wonderful how realistic most of these backings are even when seen up close and out of context.

The Scenic Painting Building on the Sony Lot (formerly MGM)

The Scenic Painting Building on the Sony Lot (formerly MGM)

Backing from The Sound Of Music

Backing from The Sound Of Music

Backing from South Pacific. Notice the inset close-up of the brush work

Backing from South Pacific. Notice the inset close-up of the brush work

Sample of photo reference for a backing along with notes and a small preliminary paint study for the final backing

Sample of photo reference for a backing along with notes and a small preliminary paint study for the final backing

small painted comp for a backing for a corridor of the first Star Trek film in 1978

small painted comp for a backing for a corridor of the first Star Trek film in 1978

Paint rack with Hudson sprayers and roller mandles

Paint rack with Hudson sprayers and roller mandles

Art Directors Guild's Associate Executive Director John Moffit in front of one of the many backings he painted while Head of the Scenic Department at Warner Bros. Studio

Art Directors Guild’s Associate Executive Director John Moffit in front of one of the many backings he painted while Head of the Scenic Department at Warner Bros. Studio

Large backing in progress on the large paint frame

Large backing in progress on the large paint frame

Still from a Life Magazine article of the same space when it was the MGM scenic shop in the 1950's.

Still from a Life Magazine article of the same space when it was the MGM scenic shop in the 1950’s.

1950's photo of a backing layout in progress.

1950’s photo of a backing layout in progress.

And finally, here’s a time-lapse video of a street scene backing being painted by scenic Donald MacDonald at J.C. Backings. Note how the canvas is back-painted so that it can be rear lit for a night shot.

 

Your Next Phone May Be A Real-time 3D Scanner

In February Google launched what they call “Project Tango”. They have developed a smartphone which is also a 3D scanner that can map the surrounding area and build a visual map of it. Processing over 3 million reference points a second, the device can build a virtual, scalable model of a room in the time it takes to walk through it.

Schematic of how the Tango device works

Schematic of how the Tango device works

They have currently hand-picked 200 developers to create applications for the device which as of now only runs on Android devices. Imagine what this would do to those never-ending time-consuming location surveys. Would you ditch your iPhone if you could have an Android phone that did this?

 

Can’t wait that long? If you’ve got $4500 and want the latest in room scanners, go over to Matterport and watch their demonstration video of their room capture camera system.

 

 

“Hand Hewn” vs. Machine Made – Part 2

In the first part of this article I mentioned that traditional hand tools could create a finish superior to their modern day counterparts. Rather than just expect you to take my word for it, I’ll show you the proof.

Traditionally the way to surface wood once it was cut to approximate size with a saw is by using various types of  hand planes.

modern woodworking hand planes

modern woodworking hand planes by Lie-Nielsen

Used for thousands of years the plane is believed to have been designed by the Romans. Basically it was a base of wood or metal which used a wedge to hold a piece of steel with a single-bevel cutting edge at a set angle to the cutting surface. Modern planes have a more refined system for controlling the cut but the basic layout of the tool is still the same.

For bulk planing it’s hard to beat a modern powered thickness planer but for some operations like fitting doors, which requires very careful trimming, the traditional hand plane excels in a number of ways. I thought I’d do a little test and compare the quality of the surface of some wood run through a power planer as compared to a hand plane.

Lie-Neilsen block plane

Lie-Neilsen block plane

the block plane in action

the block plane in action

Here’s a block plane, which is great for quick jobs like fitting doors. This particular plane is an exceptionally good one made by Lie-Neilsen in Maine. The wheel on the rear allows you to adjust the depth of the cut even while planing by as little as a thousandth of an inch.

When the blade is set properly and the plane is held parallel to the wood, you get a beautiful, continuous strip of wood that comes off the work piece. Instead of sawdust from a modern power tool you get this lovely pile of curly shavings. The bottom photo is of the final plane shaving. It’s a few thou of an inch thick or about the thickness of a piece of 1000H vellum. It’s impossible to do that with a power tool.

 

hand plane shaving about the thickness of drafting vellum

hand plane shaving about the thickness of drafting vellum

 

Look closely and you can see the individual wood cells. Great, you say, but who needs wood ribbon? Stay with me, I’m getting to my point.

 

 

 

 

 

below is a piece of wood run through a power thickness planer with a new head.

Surface of wood after being run through a planer

Surface of wood after being run through a planer

 

 

 

 

 

 

It looks pretty smooth, until you do a side-by-side comparison with the hand plane shaving. You can see below that the hand plane shaving is much smoother than the “fuzzy” appearance of the power planer sample. But why?

comparison of power planer cut (left) with a hand plane shaving (right)

comparison of power planer cut (left) with a hand plane shaving (right)

The cutting head on the thickness planer looks like this:

spiral cutter head for a thickness planer

spiral cutter head for a thickness planer

Instead of a single blade that stays in continuous contact like the hand plane, the power plane’s cutter is made up of dozens of small knives that cut at thousands of revolutions a minute, which instead of one continuous cut creates a lot of this:

power planer shavings

power planer shavings

Smoothing planes and card scrapers were used to create a finish as smooth as that created by modern tools using sandpaper. Sandpaper wouldn’t become used universally until the second half of the 19th century. Abrasive material, mainly fish skin, existed during that earlier period but was used mainly for the final polishing of a finish rather than as a way to surface wood like we do today as a replacement for planes.

One national woodworking magazine recently conducted a test, pitting a man with hand planes against another with a power sander to see which could finish a set of doors faster.The hand planes won, smoothing the pieces in less time than the sandpaper process which required sanding the pieces multiple times with different grits of sandpaper.

So why were planes replaced by sandpaper? Because you can hand a power sander to a complete novice and they will be able to get an acceptable finish with very little help. The use of hand planes requires the person to know how to use the tools as well as knowing how to sharpen and adjust them. Power tools have great advantages over hand powered tools when it comes to general output speed and during the industrial revolution they had another advantage; they allowed for the use of a fairly unskilled labor force. With power tools the real control is in the hands of the tool, not the operator. That’s why with power tools there is usually a lot of work involved in setting up or creating jigs  to gain more control over the cutting process.

Because woodworking using had tools was labor intensive, and because prices for items like furniture was usually set by local organizations, only surfaces which were seen were finished to a highly smooth surface. here’s a photo of the underside of a table in the Chicago Art Institute. You can see the plane marks on the underside of the table top:

table top bottom

 

An easy way to tell if a piece of furniture is a period piece or a modern day reproduction is to run your hand along the back of the piece or the underside of a drawer. If it’s an antique it won’t be smooth.

Traditional wood moldings were made much the same way but instead of a flat blade, the blade was cut in a reverse profile to the mould that was to be made. Here are two of the moulding planes from my collection. The oldest of the two, made in London over 250 years ago, still works perfectly once I tuned up the blade. You can see the results, a surface so smooth it doesn’t need to be scraped, much less sanded.

wood moulding planes

wood moulding planes

 

Cyma reversa cut with an 18th century moulding plane

Cyma reversa cut with an 18th century moulding plane

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Moulding plane and the profile it cuts

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

So, if the plane was developed by the Romans that should mean that woodworking before that time must have been pretty bad, right? Nope.

Take the Greeks. The Greek Trireme was as amazing ship for its time for a number of reasons.

Greek_GalleysIn the ancient world ships were built in a completely different way that we think of them. Since around the 1st century ships have been built by making a framework first and then applying boards over the frame. In the ancient world ships were built hull-first., and only after that was a structural frame added for stability. The timber making up the hull was joined edge-to-edge with what is known as loose tenons. These were inserted into slots, or mortises and then pinned with dowels through holes drilled in the sides of the timbers to pull the two pieces together making a glue-less bond that didn’t require any kind of metal fasteners. The average small Greek ship had about 8000 of these tenons.

Greek ship construction - illustration by Eric Gaba

Greek ship construction – illustration by Eric Gaba

 

More modern wood ships had planks nailed to a wooden frame and then tarred rope, or caulking was hammered into the cracks between them to make them watertight. There is no indication the Greeks used any caulking in their ships, which means they were skilled enough with their tools, adzes and chisels, to make the joint between the edges of the planks tight enough that once the wood was exposed to water, the planks would swell together creating a watertight vessel. That’s some pretty amazing woodworking.

Of course this also means that not only was Noah a wiz with a mortise chisel, since a ship the size of the Ark must have contained some 100,000 tenons, but every modern recreation of it I’ve seen is completely wrong.