Would collapsing all stacks before rendering produce better results ??

[JezUK]

I've had a bizarre situation where I sent what I completely believe to be two identical 3ds max scenes to a render farm and the ONLY difference between the two scenes being that in one of them I didn't collapse the stacks of the geometry, whilst in the other, I did collapse all stacks.....

It turns out that for me, (unless I genuinely have overlooked a difference, which I'm convinced I haven't), the render with the stacks collapsed turned out to be 'cleaner'.

Has anyone ever seen this before - is this common knowledge (and I'm the last to know about doing this) ?? Normally I must admit, I don't collapse stacks (I prefer to keep the file sizes as small as possible).

Thanks,

Jez

(3ds Max Design 2014 and Vray 2.4)

[glorybound]

I have read before that you should collapse your stack when you are done, if you are trying to optimize your scene.

[danio]

Weird! I haven't seen that but I wonder if adding an 'Edit Poly' modifier at the top of the stack would give you a cleaner effect without collapsing? Probably not, but just a thought.

[bardo]

just a possible cause.
have you some "rendertime" modifier in the scene??

I'm explaining with an example.
If you have a modifier that modifies the geometry only during the render, you'll have obviously some differences in the GI calculations.... something like VrayDisplacementModifier

[Dave_Wortley]

Certain modifiers create extra channels of information, collapsing them down reduces the number of channels and in certain cases can heavily speed up your scene as certain modifiers are very CPU intensive to evaluate and a collapses mesh will often be quicker. I have a script somewhere which collapse all modifiers that aren't render-time dependent, ie TurboSmooth VRayDisplacement etc...

[JezUK]

Well done guys and thank you

I can confirm that there were VrayDisplacementModifiers on a few carpet objects within my interior and I guess that was what made the difference.

Great to learn something as important as this - I really appreciate it and will ensure to collapse stacks in future.

[eyepiz]

Would you mind sharing the script?

Certain modifiers create extra channels of information, collapsing them down reduces the number of channels and in certain cases can heavily speed up your scene as certain modifiers are very CPU intensive to evaluate and a collapses mesh will often be quicker. I have a script somewhere which collapse all modifiers that aren't render-time dependent, ie TurboSmooth VRayDisplacement etc...

[Dave_Wortley]

Would you mind sharing the script?

I'm afraid it's a bit engrained in one of our asset tools, there's a lot of UI stuff that goes with it to allow any type of modifier to be excluded from collapsing.... And there's some other funky stuff that happens for hierarchy, transforms that's kind of essential to doing a collapse correctly. It's often not as simple as just right clicking-> Convert to Poly.