Irradiance map settings for animation

[stargazer424]

I have a few questions about render settings for animations. I'm working on a project for work which consists of short (2-3) second walkthrough animations of 3D rooms. I have already set up the objects and lighting using Irradiance map and Photon Mapping. Now I am trying to figure out the settings for the animations.

 

Most of the time it will just be a moving camera with no animated object. My first question is, can I use the "Multiframe incremental" setting for the IR? From what I have read this should work for a scene without animated objects.

 

However some of my scenes will have animated objects along with the camera, such as a cabinet drawer opening. Here I assume that the Multiframe incremental will not be able to calculate the space where the drawer opens correctly. Therefore I'd probably have to use "Animation (prepass)" or single frame. My second question is, does the prepass really save any time? I ran a prepass last night, for a 60 frame animation (@24 fps) it took around 5 hours. If I did single frame, wouldn't it need to take the same 5 hours to render each IR frame by frame?

 

 

Also, are there any issues with using Photon mapping with these scenarios? All the posts I have seen so far have used Light Cache instead.

 

I am rendering at 900x500, most of my renders have taken about 20+ minutes per frame. That is over 20 hours for a 60 frame animation. I don't want to compromise quality but is there a way to reduce final render time?

 

Thanks in advanced.

[Devin Johnston]

If there are no moving objects in a scene Multiframe is the way to go but as soon as you have moving objects you have to use animation prepass because if you don't shadows won't be calculated properly. It's really not about saving time when it comes to multiframe or prepass in fact I beleave prepass is much slower, what your trying to do is get an accurate GI calculation so everything looks correct. Photon mapping is an older engine that has been replaced by the faster light cache engine, unless your doing something that absolutely needs photon mapping I'd use LC.

 

20 min per frame really isn't that bad it just depends on what your rendering, there are unlimited ways to speed up a rendering but it's scene dependent and it's really impossable to say what you should change without seeing what your setting are.

[Tommy L]

With Multi-Frame incremental you dont render every frame, thats where the time saving is. You would render say every 10th frame. The light map is interpolated between the calculated frames. In fact, it is also added to the file, so if it sees stuff in 2 frames, there is a time saving there. Yes, Multi-frames the one you are best using.

Opening doors etc are a cliche, I'd not do it if I were you....but the technique would be to tell animated opbjects to not generate GI.

Light cache would indeed be the best/fastest/cleanest secondary GI.

The way to speed up the rendering is either refine your material/light/AA/render settings or to get more power.