deep shadow problems

[borisb2]

Hi.

I'm having big issues with rendering deep maps.

I've go a character that is casting shadows on a groundplane. The camera is fairly low-angle (but not AT the bottom), I guess thats the reason why the edges from that groundPlane starts to get shadow-edges in the alpha. Even when I scale up the plane the edges doesnt dissappear. When uping the shadow bias to 2-4 it starts to go away, gut that would not be ideal because the characters shadow also moves away from the beauty (because of the hi bias) .. also by raising the angle I can see the errors fade away.

Can I do somehting more about it? The camera is tracked, and I dont want to render with shadow-bias 10?? Is there anything else I could do?

Thanks for any help

[Macha]

Could you set it to raytrace or pbr and render out a shadow pass that way or is there a special reason you have to use deep shadows?

[borisb2]

yeah.. rendering millions of point particles.. thats why I was using nicely blurreed maps at the moment.

raytrace shadows flicker a lot of course. Would pbr help? .. or maybe use of area light and raytrace shadows? But I guess for millions of particles it will shoot up rendertime a lot..

[Macha]

I have good experiences with pbr, shadows and points. I find it very fast. And you can maybe get away with less points for shadows?

Another thing to try, though at first glance it didn't seem to make a difference, is to inspect the shadow map file itself and see if you can get rid of noise or anything. However, I think the problem lies in the way the renderer interprets the map, not the map itself, but perhaps somebody knows more about it.

Edited November 10, 2010 by Macha

[borisb2]

here's the alpha of a test rendering of the shadow pass. As you can see the border of the groundplane gets this grdient, no matter how big that plane is.

At a bias of 3-4 it fades away (but with also half of the wanted shadow biased away)

There must be a setting somewhere.. Again, I'm having particles to render - is there another method than deep shadow maps to efficient render selfshadowed particles?

[Macha]

If you open the deep shadow map (in mplayer if its .rat), does that border coincide with the border of the shadow map by any chance?

[borisb2]

no, its far outside the shadow map .. I can see that also by looking through that light.. must be something with the bias?

[SpencerL]

no, its far outside the shadow map .. I can see that also by looking through that light.. must be something with the bias?

it almost looks like the cone of your light. Maybe try having your cone bigger so that it includes the entire plane in camera?

Edited November 11, 2010 by SpencerL

[Mzigaib]

Try to increase the bias on the map shadow, maybe this would help.