Texture projection on instanced geo

General TouchDesigner Discussion
1

Hi,

a general question on texturing instanced geo:
I’d like to project a texture on an array of some imported geometry. I tried to use a texture SOP with the camera projection option. It works with a single geo but if I try to distribute it to like 10x10 instances, using a geo COMP, the texture of course gets multiplied as well.

How can I make a camera projection go across the instances as if they were one single object?

Do I need to write a GLSL material like described here to work with the instance positions and ids or is there a simpler built-in solution, I’m overlooking?

2

If I’m understanding what you’re after there are a few ways you can approach this - one would be to use the uv offsets in instances to use a single texture across instances. Another technique would be to use a light to project a texture onto your scene. Does that all make sense?

3

Thanks for pointing me at the right direction.

Projection with a light COMP basically does what I was after. This example from the wiki helped:
Projection_light.tox

Regarding the more procedural uv-offset approach, I also would like to use. I’m trying around with the uvw parameters on the Geometry COMP’s “Instance 2” Page but I’m unsure how to define the offset so the UV range spans the whole array of instances.
how_to__uv_offsets.toe (6.22 KB)

4

I know there’s an example of uv offset in here:

github.com/raganmd/touchdesigne … g_examples

Here’s your network modified to use uv replacement and uv offsets.

I use offset when I want to break up an image and sample it across instances, but maintain the original composition.

I commonly use replacment when I want to use the normalized location of an instance as a sample location for color - a al 8bit style art, etc.

When offsetting it’s usually important to use a texture SOP to help scale the UV range of a given geometry to make slicing up your sampled texture a little easier.

Here’s a look at how to get there:
how_to__uv_offsets.7.toe (5.29 KB)

5

Matthew - that’s just great. Wow! Thanks for the help!

Really good learning resource.
(asking myself how could I miss those)

6

glad it’s helpful!

I have a few things in there that I need to clean up and change - on the long list.

Instancing is one of the most powerful features in touch - well worth really digging in to learn and understand. :slight_smile: