Render is not the same as viewport!

[inganni]

Hello everyone!

I have been trying to solve this problem for days now and I'm starting to get desperate..
I'm trying to render an animation with batch render but something goes wrong.
My main object is supposed to move around a lot which is why it has a "point on poly" constraint and there is also supposed to be a stream of particles emitting from within the object.

When this is rendered out the object moves around as it should but sometimes it makes violent jumps, particulary in the rotate X attribute. Now, I know this is most likely caused by the strange way the constrainted vertex tend to "rotate" (normaly not even seen). I solved this by counter the rotation, key framing offset rotation X when it was needed.

So now everything looks good when creating a playblast or simply playing the animation in the viewport.

However... since the rendered animation still had those jerky movments I started to suspect that "batch render" was the problem.
That it somehow produced a slightly different result than the viewport so I downloaded an automated viewport render script but it still did'nt work.. For some reason I missed it before but you can easily see that the normal render produce a different result than what the viewport is showing.

And btw.. I play the animation from the beginning so that the particles are emitted as the should and it's also easy to see that the object behind the particles is still in a different location/rotation than the viewport.

so PLZ! If anyone knows what's going on... please tell me

/Johan 

[joojaa]

Before you batch render you need to make a particle disk cache using  [dynamics] -> Solvers -> Create Particle Disk cache. The run up routine of the batch doesn't work in same timespace as the normal maya*. That should fix things if not then you have some other problems such as a ascript that reacts to the gui, which is something you should never ever have. Unfortunately people tend to have bad understanding of  the implication of such things.

• this is not really considered a bug. If you would have a renderfarm then you would absolutely need to make a particle disk cache anyway or loose a big part of the benefit of the renderfarm. Since autodesk imagines EVERY serious client has one they understand that this would be the case. Its well documented, in fact maya warns you of this.

Also baking data down is something you should allways do anyway wheever you encouter a problem. Or rather every time you send something to render in fact.

[inganni]

Thanks!

I used the disk cache which helped me some. At least when it came to re-render som failed frames. Which was hard before due to the randomness of some particles.  Allthough the problem with the jerky movment of the main object (with point on poly constraint) still remains. Since the jerky motion is only visible in the rendering (both batch render and normal render) and not in the viewport I was considering the script problem.

The poly to wich my object is bound to is animated using a displacement script that of course is responible for the movment of my object. If it's possible to cach this movment or not I don't know. One solution might be to offset the rotation of the faulty frames until they look good when rendering and not in the viewport.. will take a while but might work.

anyways.. thanx for the help!

/Johan