Outputting content from TouchDesigner to a projector is one of the most common tasks you’ll find yourself encountering as a developer, whether you’re working on personal art projects or commercial installations. Using a projector opens up a lot of new possibilities, including the ability to map projections to irregular surfaces or to cover large surface areas by blending together the output of multiple projectors, but also introduces complexity into the process when compared to a traditional display.
Thankfully, TouchDesigner has a lot of great tools for working with projectors which make the process easier!
In this post, we’ll cover a number of tips for working with projectors and TouchDesigner, by looking at what built-in tools you can use to accomplish common projector-related tasks including keystoning/warping, projection mapping, and more.
First Steps: Outputting from TouchDesigner to a Projector with Perform Mode
If this is your first time outputting content to a projector in TouchDesigner, start here!
You’ll likely want to set the project up to run in Perform Mode (a performance-optimized mode for live performances/installations alike), which will require the addition of a Window COMP to the project. The Window COMP allows you to create and maintain a separate floating or fixed window displaying the content of your choice (generative content, video file playback, etc.), and is what you’ll use to display content on the projector.
We’ve recently put together this video which covers how to set up your project to run in Perform Mode, and would definitely recommend checking it out if this is your first time doing so!
Keystoning and Warping with Stoner
If you need to manually fit an image to a 3D surface, Stoner is a great tool to start with. It offers the ability to perform simple corner-pin image warping, but also can get much more complex with mesh warping of the image. This feature, called Grid Warp in the Stoner user interface, also allows for the grid used to make the warping adjustments to contain a flexible number of rows and columns.
Projection Mapping by 2D Masking with Kantan Mapper
If you’re looking for a (somewhat) MadMapper or Resolume-style projection mapping and masking tool where you define 2D polygons and bezier outlines in the field of view of a projector, look no further than Kantan Mapper!
Kantan Mapper allows you to create a wide range of shapes for getting your mapping just right, from simple rectangles to more complex bezier curve-based freeform shapes. Like Photoshop, new shapes are added as layers which can be adjusted after the fact. Along with that, grid warping like we looked at in the Stoner tool can be applied to rectangle shapes with a flexible amount of rows and columns. There are also options for feathering the edges of either shape type as well.
After defining the shape, you can then apply a texture to it using a TOP. There are positional adjustments for deciding what portion of the texture will be applied to the shape, along with the ability to use the shape to mask the texture.
For situations where you’ve got a number of irregular surfaces to map your projection onto, Kantan Mapper can be a great option!
Highly Accurate Mapping with a 3D Model of Projection Surface: CamSchnappr
Happen to have a 3D model of your projection surface and are looking to speed up the mapping process? Check out CamSchnappr!
CamSchnappr is an adaptation of mapamok, a projection mapping tool developed by Kyle McDonald at the YCAM Interlab (source code and technical information here). It’s an amazing tool that both simplifies and greatly speeds up projection mapping, provided that you have an accurate 3D model of the surface that you’re looking to project onto.
If you do have (or are able to create) a 3D model of that surface, you can perfectly align your projection by selecting and aligning 6 or more alignment points on the 3D model to the physical structure with the camSchnappr interface. Once you drag the points to the correct location, the projection just “pops” into place—it’s pretty incredible!
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These templates shed light into the most useful and sometimes obtuse features of TouchDesigner.
They’re designed to be immediately applicable for the complete TouchDesigner beginner, while also providing inspiration for the advanced user.
Blending Multiple Projectors with projectorBlend
If your project requires the use of multiple blended projectors, projectorBlend is the tool for you! Based on the ofxProjectorBlend add-on for openFrameworks by Jeffrey Crouse, it allows for the blending of projector arrays. projectorBlend can be used for setups as simple as two adjacent projectors to much more complex arrays of many projectors.
projectorBlend gives you all the controls you need to adjust the blended area of the projection, including luminance, gamma, and HSV adjustments. When working with more complex projector arrays, you also have the ability to either set up universal values for all edges of the image, or to make adjustments for each edge of the image separately.
The underlying technique that is used for this tool is based on the 2004 paper Edge blending using commodity projectors by Paul Bourke. It’s actually a very helpful resource to read through to better understand how the effect works and should be used. We’d definitely recommend giving it a read if you plan on using projectorBlend in your project!
Other Tools and Resources
Although the tools we’ve covered so far are some of the most commonly used for working with projectors and TouchDesigner, there are still more tools that come with the program!
If you’re looking to create trompe l’oeil projection effects, check out sweetSpot in the palette. It can be used in conjunction with the camSchnappr COMP to render a scene from the position of the observer and re-project it onto a surface, allowing for convincing illusions of depth (when viewed from the right position).
In the Derivative documentation, check out the page on Projection Mapping, which outlines all of the various tools for projection mapping that come with TouchDesigner.
Over the years, a number of useful videos regarding working with projectors and projector mapping have been posted to the Interactive & Immersive HQ YouTube page, which are well worth checking out as well (especially to see the process of actually using the tools we’ve covered here). Here are a few highlights:
Wrap-Up
It’ll take some practice to get the hang of some of the more advanced techniques we’ve covered like projection mapping, but it goes without saying that the tools included with TouchDesigner make the process of working with projectors much more straightforward, regardless of application. We hope that this post has been a helpful introduction to the many tools that TouchDesigner offers for working with projectors.
