Hi,
I would like the instanced objects to fade in gradually after they are emitted  in 10 frames. How do I do it ?
I have tried adding a ramp in the per particle opacity. It shows me the transparency in the shaded viewport but is fully opaque when I render it.
Thanks,
Redman

The shader you apply to the instanced object  is not going to respond to any per-particle attribute. It's been a missing feature for years. Please log a feature enhancement request with Autodesk. The workaround is to cycle through 256 objects, each with a slightly different opacity.

Well if its any consolation it CAN be done with mentalray, if ones prepared to wirte 60 lines of mentalray shader code. However the tools needed are a bit convoluted.  Anyway this has been requested year uppon year.

On the upside rendermans studio doe sthis natively.

Also 10 difefrent objects would probably suffice.

Whoa there... Can't you just animate the transparency value of the shader being used on the instanced objects?  Or, the Cutout Opacity value of a Mental Ray shader?  

Err... Wait do you mean that each instanced geo/Particle needs to disappear at different rates?

Make 10 copies of your object and give them s shader thats progressively more trasparent and swap the isntace out in isntancer. Thats the 3rd and 4th answer.

However it is possible to do this its just that autodesks mr exporter is made in a bit retarded way* and its not easy to do a shader like this. Its possible tough just  a bit convoluted. If your comfortable writing c and compiling mr shaders then i can give you a walk tough on how to do this properly.

*well thing is the mi stream seems to have absolutely no design principle behind it whatsoever, or then its designed totally wrong way around. Its not like designing it in way that makes more sense is impossible. Maybe its due to the fact that they wanted to go the bundling way but still...