Need help with displacement maps on instanced particle objects

[Anonymous]

Hello! 

New to the forums and to Maya, working on a student project (Maya 2018 Educational version). It's an asteroid field for a film (Windows 10).

I made six asteroid shapes (low poly), and created a warped looking torus that I created an emitter from. The torus emitted nparticles that I basically instanced my asteroids to distribute along and gave them randomized rotation/scale attributes so they all look different.

The asteroids I got to animate and distribute fine, but my problem is rendering and displacement maps.

I'm trying to Arnold render these bad boys out, and my displacement map worked for the source objects that the nparticles derive from, but not for the (excuse the lack of proper jargon, still a beginner) "particle'd" asteroids. Does it have to do with caching or something else? Do I need to go in and manually adjust the attributes of each particle (is there a MEL script that could partially automate that process)? Thanks a bunch and sorry for the inexperience.

The following screengrabs are to help show what I'm working with, sorry if it's messy or disorganized... Self-taught and learning (less than 2 weeks so far but enjoying every moment), so I'm certain I'm doing very inefficient things here and there!

Thanks again,
Andy W.

A rough example of the displacement map working on the source objects.particles not showing the displacement despite being the same objectshow the asteroids are shaded.some settingsarnold subdiv/displacement settingsexpressions

[mspeer]

Hi!

For Arnold check Attributes below:

Arnold -> Subdivision

Arnold -> Displacement Attributes

[Anonymous]

Thanks for the reply;

I did do that already actually, and it works on the objects themselves but not when they are instanced as nparticles, which is what I can't get working. Does that make sense? 

I very much appreciate your time and I'll keep trying things.

[mspeer]

Hi!

Yes i understand what you mean, but here it works.

What Maya / Arnold version do you use?

You could also upload a (simplified) scene-file.

[Anonymous]

Gotcha, I am using the educational version of Maya 2018, don't know Arnold off-hand and won't be back on site till tomorrow, I can find out and let you know and can send a scene file then too.! Thanks and sorry, yeah not really sure what is happening, but I can't thank you enough for helping.

[mspeer]

Hi!

"I am using the educational version of Maya 2018"

- This is not what i meant i meant the release version. Maybe you need an update for Maya and Arnold.

[Anonymous]

Hello again, 

Sorry, I misunderstood. As a student, I am using software provided within the program but they restrict access to updating and such. What I have is what I got, and unfortunately, I'm not sure where to check which version that is if my previous information was insufficient. As it is the weekend, faculty aren't contactable regarding requesting updates,  but I was doing some research and found better, more concise terms for what I am looking to do:

Can you override shaders/materials to objects in a collection (instancer/emitter, nParticles to objects)? I found on an old forum post from another website from 2008, someone had the same issue in 3DS Max, and it was resolved, but unfortunately photos posted to the forum are no longer existing to reference.  This is what he said:

...For my displacement, I used the displacement slot on a material, and applied a “Displacement Approx” to the object (which works fine for non-instanced geometry). However, since this doesn’t change the mesh until render time, I’m guessing that my Instanced Geometry can’t “find/read” that...

Do you think there is a way to override the instanced objects' shaders?

Thanks again! I'll keep you posted re: the versioning and stuff when applicable.

EDIT: I also realized, I never used MASH, should I have?

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[mspeer]

Hi!

MASH uses the sane Instancer node, so this will not change anything.

Please upload a scene-file. (Original object + 1 particle/instance + displacement texture.)

[Anonymous]

Hey, When I made a mini project file, with a single particle object ID instanced, it rendered fine; I'm going to try to recreate the problem by replicating the process I did on my main scene in a smaller scale and try to identify the source of the issue. Thanks!