Texture sampling for non grid based instanced geometry

I’ve had lots of success with geo instancing using a grids for pos and also sampling the material color etc

But how can this be done with non grid based instancing?
I want to use the points of circling circles for the instancing points but get their point color from a top, like you would with grid point instances. But I assume that is only using indexing of color positions and not sampling the position of the TOP.

Im not sure where to start on this.

Attached is tox of where Im at if it helps

thanks for any help

ringbase.tox (4.8 KB)

I’m not sure exactly what you’re after, are you just trying to change the color of each instance and make them in a rotating set of nested circles? There is an instance set of channels available for this in which you can set a different source data OP than the main instance OP.

As well you can convert sops > chops > tops and then use Point Transform TOP to more efficiently transform your instances before putting them all into a single TOP for instance data. You could make a shader to do this in less OPs as well, though that means doing transform work in the shader which requires some knowledge of GLSL and TD GLSL functions.

Anyways, I’m attaching a tox with something like this and some notes in DATs that might be useful to you.


instancedCircles.tox (4.2 KB)

Thanks so much. Lots of new techniques to get my head around. At this point it does look like what I need.
thanks again

One quick question please.
The Null positionsInstTop seems to be showing comp1 as the position points. What is happening and how is a null doing this?

Ah, yeah. For a little while now TOPs have had an alternate viewport mode, can toggle it on off by pressing “v” while the node is active that displays the RGB data as XYZ points, very useful for checking these things prior to using in instancing or other workflows. Any TOP can be viewed in this way, though it wont mean much if it isn’t intended for XYZ usage.