CGTalk - Shadow Pass problem...

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aazimkhan

01-09-2003, 04:44 AM

Hi guys,

I got a scene with trees, the trees are simple grids with Alpha map tree pictures.

Due to very slow rendering, i decided to render my scene in layers.

So my scene is now rendered in 2 layers a normal and a shadow pass.

Now heres the problem, when i render my scene normally in single pass the shadows of the trees are real, i mean it gives the the actuall tree outline shadow using the alpha.

BUT. when i render it in a shadow pass it gives the shadow of the grid ( grid shaped shadow) and not using the alpha image to cast the tree shadow.

How do i fix this, i tried playing aorund with the render tree in shadow pass mode....

please help me!!!!

thanks

aazimkhan

01-09-2003, 04:49 AM

heres how it looks in normal render

aazimkhan

01-09-2003, 04:53 AM

and heres how it looks in shadow pass:annoyed:

belly80naz

01-09-2003, 02:25 PM

What do you want to say with "very slow rendering"?
For my attached image, my P4 2400 Mhz render it in 2 or 3 seconds.

But also, I've got the same problem and I don't know why the shadow pass is so. I think that can to be a XSI's bug but I'm not sure.

We must hope someone have the solution.:shrug:

aazimkhan

01-09-2003, 02:32 PM

thanks for the effort,

yeah i think so too thats its a bug.
coz the grid with the tree picture gets a differnt render tree when in shadow pass mode, its has a material node....with two other nodes...shadow and siple shadow attached to it....so it loses the picture information.....there is a option where u can attach another trasparency map to the shadow....but that gives off a different effet.....

and yeah i got lots of those trees in my actual scene with other heavy models.......whihc will be rendered at720x486 with motion blur.
i got a p4, 1.8

PS: i am working on my animaion project
http://www.aazim.odhn.com/wip__total_control.htm

thanks, hope i can find some solution to that....

Atyss

01-09-2003, 03:03 PM

You will have to build the shadow pass from scratch.

In this empty, put an override on the default partition.
In this override, add the following parameters: diffuse color (select the diffuse folder of the material) and specular_inuse. Don't forget the _inuse bug and the script thing to overcome it.

Disable specular.

Select the override, and open the render tree. Create a color_savestate node, and connect it into the surface-material-diffuse-color input of the override node. Set the Color_savestate to black, including alpha.

Now if you render, everything should be working fine. You might have to set the alpha value of the Color_savestate node to 1.0.

I don't have XSI in front of me now so I can't test it out.

Hope this helps
Salutations - Cheers
Bernard Lebel

zen

01-17-2003, 02:44 PM

just a question...

you using shadow maps? Cause i ran into a problem i cant seem to fix tosay: shadows created from light with shadow map enabled wont recongnize alpha transparency. It just outlines the model.
Maybe cause its a GL raytrace?

if anybody has an answer for this dont be shy....

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