Shadow Maps

[HMA_Steve]

Not strictly a Vray question but hopfully someone can answer.
I have a number of point lights in a scene, all have shadows on and use shadow maps (renders quicker than vray shadows). The only problem is that it has to calculate the shadow on each frame but there are no moving objects so this is not necessary. Is there a way to force it to just calculate the map on the first frame only? I was under the impression that it was supposed to do this anyway but for some reason it calculates on all frames.

Thanks in advance.

[percydaman]

i think ive heard it can be done in other packages, but not sure you can in max/vray.

[joconnell]

Not in max afaik - it's one of the benefits of something like renderman where you can cache shadow maps and even paint them if you want since they're only bitmaps. Optionally if you're using area lights and irradiance mapping you can use the store with irmap options so you don't take the raytracing hit each frame.

[HMA_Steve]

shame, its still a bit quicker to use the shadow map but would shave a good 10 seconds more a frame off if it didn't have to calculate each frame.

[vlado]

In fact, the shadow maps can be reused in 3dsmax, if the renderer keeps track of whether anything in the scene has changed and relays this information to the shadow map plugins. V-Ray does not do this at the moment and forces the maps to be recalculated on each frame, just in case.

Best regards,
Vlado

[joconnell]

Probably safer that way - one less thing to keep track of.

[HMA_Steve]

ahhh! i thought i had seen this happen in the past. must have been before i used vray.

[dimo]

Hi,

one thing you should be aware of with shadow maps is that they are rendered with the scanline renderer. This means they don't see:

-Vraydisplacement
-VRayProxies
-All Vray Primitives (VRayPlane, VRaySphere etc.)

Best regards,

Dieter

[Candelero]

And in addition !
Shadow Map - doesn't recognize materials, when it comes to opacities. It just reacts on geometry.


Best regards,
nikki Candelero

[HMA_Steve]

all true but they're great in some situations where you want a softer shadow thats quick to render and you're not too bothered about accuracy or using any of the things you mention.