teaching > Projection Mapping

2015-08-18

Intro to Projection Mapping

Projection-mapping techniques allow you use software to paint with projected light onto physical shapes. Projection mapping is an effect of Chiaroscuro, which is an art that “uses of contrasts of light to achieve a sense of volume in modelling three-dimensional objects and figures.”

Instructor:

Gabriel Dunne gabe@gabrieldunne.com gabrieldunne.com

Workshop History

Meeting Times

Day 1

Quad Mapping

Typically the light cast from a typical projector is a rectangle, representing an rectangular screen output, a most content built for screens are in a rectangle shape. To throw a rectangular imagine into a specific area, we “corner pin” the quad, with four movable points. Using this hand-mapping technique, we can draw a series of rectangles that are aligned onto a space or object. This is great for:

Using Processing

In the examples/ folder, you will find a few Processing sketches. One of which is an example that uses Projected Quads, based on a processing sketch by Marcin Ignac. Navigate to the examples/ folder in this repo and open ProjectedQuadsGLShaders, for example.

Features:

Key Commands

'SPACE' toggle debug mode
's' save settings
'l' load settings
',' select next quad in debug mode
'.' select prev quad in debug mode
'1', '2', '3', '4' select one of selected quad's corners
Arrow keys (left, right, up, down) move selected corner's position (you can also use mouse for that)

Demo of this sketch in action, as used by Stephanie Sherriff for her “Whitish Paintings” series.

Exercise

Load your own content into these sketches, and quad-map the content.

Day 2

Mesh Mapping

By manipulating a mesh, we begin interleaving physical form and software geometry. Starting with a 3D object, which can be created in a variety of ways. You can use 3D modeling software, like Sketchup or Rhinoceros 3D, Maya, Cinema4D.

There are a variety of methods to scan forms, using a depth camera, 2D camera vision, or 3D laser scanners. Even DIY methods.

OpenFrameworks

Computer Vision

Computer Vision techniques use matrix transformations to approzimate focal distortion through a lense. This method distorts the frame of reference based on a pattern, or markers on a physical object, usually read by a camera, sensors, or manual input.

ProCamToolkit is a modular toolkit developed with YCAM Interlab by Kyle Mcdonald, built with OpenFrameworks. It’s collection software and code for openFrameworks that uses camera vision to aid in projection mapping tasks.

Mapamok is a module of ProCamToolkit used for for exploring projection mapping. It includes features for matching geometry to space using camera vision and calibration tools.

Optical Mapping with Mapamok

Download Mapamok

After downloading Mapamok, grab the grandtheater.dae file in the assets/ folder of this repo, and put it inside Mapamok data folder. Rename the “grandtheater.dae” to “model.dae”. You’ll have to rename the original “model.dae” to something else.

Then, follow along with the [Mapamok Tutorial](https://github.com/YCAMInterlab/ProCamToolkit/wiki/mapamok-(English).

The concept of Mapamok has been ported to Touch Designer with CamSchnappr

Exercise

Align a 3D object to a physical shape via projection. Choose a simple elements such as a corner, or a window, or a doorway. Deconstruct your shape down to its component parts and try to use modeling primitives in a modular way.

Day 3

Projectors

DLP

DLP stands for Digital Light Processing. These projectors use an array of tiny mirrors to reflect light toward the screen (an “on” pixel) or away (an “off” pixel). A informative video on the technology. Most use a color wheel – literally a spinning wheel with color filters – to create sequential color. Some high-end models use three DLP chips; one each for red, green, and blue. DLP projectors range in price from a few hundred dollars to tens of thousands, and more. Most projectors in movie theaters use DLP. A challenge imposed by DLP projectors is that unless you are filming them with a high-end camera, you will see banding on most consumer digital cameras.

Pros of DLP:

Cons of DLP:

LCD

LCD, i.e., liquid crystal display, is the technology found in most TVs. LCD projectors use three liquid crystal panels, each tasked with creating an image using just one of the primary colors (red, green, and blue). All three are projected on the screen at once, so you see a full color image. LCD projectors range in price from a few hundred to several thousand dollars. LCD projectors will film properly with hand-held and consumer cameras, they are ideal for documenting projection works.

Pros of LCD

Cons of LCD

LCoS

LCoS, or liquid crystal on silicone projectors, came along at about the same time as DLP powered projectors. It is a bit of a hybrid between LCD and DLP LCoS technology is also referred to as reflective LCD, while individual manufacturers use their own names. Sony and JVC are the primary manufacturers of LCoS projectors, which they call SXRD and D-ILA, respectively. LCoS projectors range in price from a few thousand dollars to a few models that are in the tens-of-thousands range.

Pros of LCoS:

Cons:

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Projector References:

In-Class Lab

Examples

Pablo Valbuena

Xavier Chassaing

Dev Harlan

AntiVJ

Obscura Digital

Bot & Dolly

Nobumichi Asai

Masaru Ozaki

Kyle Mcdonald, Jonas Jongejan

More…

Software

Any software is usable if it can create, distort, and texture geometry and/or flat planes.

Code Frameworks

Software Packages

Automatic Calibration

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