Animation Fade-in with Mental Ray

[jmartel_risd]

I'm doing a really basic animation where an object needs to be faded in. I've tried adjusting the visibility, and changing the material opacity, but when I render it using Mental Ray, the object is always 100 % visible. Even when visibility is set to .001, I can see it perfectly.

Does this technique work with Mental Ray or should I be trying something else?

[Justin Hunt]

Object visability doesn't work with mentalray, rather use a mix map animated over time to go from totally black to white in the transparency slot.

 

JHV

[nisus]

yeah this sucks... this messed up an animation I had to do recently... I had keyframed +1200objects over 3600frames with the visibilty track on almost every object... ow ow ow

 

nisus

[Tommy L]

yeah this sucks... this messed up an animation I had to do recently... I had keyframed +1200objects over 3600frames with the visibilty track on almost every object... ow ow ow

 

nisus

 

So what did you do?

[nisus]

I left it as it was because I ran out of time... It was an assembly-animation and instead of the parts fading in, they just popped up. Wasn't that smooth, but not really that bad either... horrible... Should have checked it upfront...

 

nisus

[Nils Norgren]

One possibility would to render it as a separate pass and handle the fade in compositing. Better yet (for GI reasons) render the animation without the object to the point the fade in ends and render a version with the object from where the fade starts through to the end. When you fade from one clip to the other the object will appear (with all the reflections, shadows, etc.)

 

My 2¢

 

-Nils

[Tommy L]

I left it as it was because I ran out of time... It was an assembly-animation and instead of the parts fading in, they just popped up. Wasn't that smooth, but not really that bad either... horrible... Should have checked it upfront...

 

nisus

 

Bummer

[daniohayon]

I'm doing a really basic animation where an object needs to be faded in. I've tried adjusting the visibility, and changing the material opacity, but when I render it using Mental Ray, the object is always 100 % visible. Even when visibility is set to .001, I can see it perfectly.

Does this technique work with Mental Ray or should I be trying something else?

 

I animate the fade through the transparency amount of the material and make sure the IRO is 1(no refractions), it worked well for a construction sequence presentation.

 

In some cases when the model has some inner faces(holes and so), you can see some details way before the object is opaque due to the fact that these areas show the material twice(not two faces but four), then you should check Back Face Culling in Advanced Rendering Options(Material editor).

 

I can post a clip later if you need...