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View Full Version : Some kind of shader/lighting flickering problem.


PandorasKeyboard
01-05-2012, 08:15 AM
Hey all, hope someone has an idea of what's going on here.
I've made a character and he's all shaded and textured on another layer.
I can see the small fixable problems with the geometry on the belt and the hand displacing the wrong way...
However he's not finished and I decided last night to blast out a turntable of him just white with displacement and normals.
Anyway it turned out like so
http://vimeo.com/34601369

There's some kind of strange flickering occurring. This is rendered with Vray and the GI is Irradiance Map primary and Light Cache secondary.
Any ideas before I try rendering again?

Cheers

Jay

Could Irradiance map being set to single frame be the cause of this sort of thing?

gcr113
01-05-2012, 09:19 AM
Could Irradiance map being set to single frame be the cause of this sort of thing?

Nope, that's actually the setting you want to use for animation. Single Frame means that a single irradiance map is calculated for the entire image (rather than splitting the image into buckets) and a new map is calculated for each frame.

It's flickering because the irradiance map quality is too low. What preset are you using for the irradiance map? The quickest test would be to bump that preset up to at least 'High Animation', change your image size to half or quarter resolution, and render another turntable while you relax and have a coffee.

PandorasKeyboard
01-05-2012, 10:11 AM
Ah cheers Greg,
I was using high, not high animation rendering at 720 * 1280
I'll have a try at boosting the preset and lowering the resolution for a quick test to see if it fixes it.

Azrail
01-05-2012, 03:09 PM
For VRay I would suggest not to use irradiance map when objects are moving. If you're rotating the camera around the object you can bake the irradiance in few frames and then use it in Read From File mode. But if you're rotating the figure then you better use another GI combo - Brute Force/Brute Force or Brute Force/Light Cache.
There are some tutorials on rendering moving objects with irradiance map on the vray help page (nvm that they are for 3dsmax), but still I would advice you to use the brute force solutions.
Rendering an animation with moving objects (http://www.spot3d.com/vray/help/150SP1/tutorials_anim.htm)
Rendering an animation with moving objects II (http://www.spot3d.com/vray/help/150SP1/tutorials_anim2.htm)

PandorasKeyboard
01-05-2012, 08:39 PM
Thanks a bunch for the quick replies.
Turns out the flickering was cause by the light cache
http://vimeo.com/34630998

The video on the left was Irradiance/light cache and the right was brute force/ light cache and the middle was double brute force.

Therefore must have been light cache that was the problem.
I'm going to boost it back up to HD and render a full turn of it with irradiance/brute tonight
Only I'll change it to the camera rotating round rather than the model spinning and have a go at the baking frames and using from file.

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