Hey @peter_horvath,

So, you do call InstanceObject.GetInstanceMatrices() etc. and construct the clones yourself. That was what confused me in your fist posting, as you talked about 'clones' in 'We'd need this index to be able to export MoGraph attributes to each clone/instance.'

What you effectively want to do, is associate the matrices/colors in an multi InstanceObject with the MoGraph particle IDs they have been created for, right? That is not possible, at least for all cloners which have more than one particle geometry. I briefly talked with the current developer of MoGraph, and he does not see an option either.

I also tried to have a look at the Redshift code base, and as far as I can see, they simply seem to unravel things from the MoData side and mostly ignore the true cache and then end up with the ability to match a clone with its particle index even in Multi Instance mode (that is at least what it looks like to me, I have reached out to one of their devs). In the end I do not see anything particularly bad with this approach, because when syncing scene graphs, you have to reallocate geometry anyway. The problem with this is that MODATA_MATRIX does not reflect the deformed matrix, i.e., it does not respect BaseObject::GetDeformMatrix and with that simulations like for example RBD. I have absolultely no idea how Redshift handles that, I might be misinterpreting their code.

So, long story short, what you want to do, does not seem possible at the moment for externals. But the MoGraph Developer mentioned that we could try to store the InstanceObject::GetInstanceUniqueIP in the MODATA_ALT_INDEX . But we would have to check first that this does not break anything. When you really want this, I would suggest filing a feature request (your Nodes API menu sorting thing is still cooking btw.)

Cheers,
Ferdinand

Editor and viewport colours - where/how to find them?