Shadow looks really weird!

[mitchbraggart]

Hi everybody!

Currently i am working on the texturing of a character in Maya 2009! While doing that i discovered a weird shadow problem!

As you can see the shadows on his clothes on the left side of the picture are not rendered right!
This problem occurs on several places on the character.

My suggestions are that this could be a raytracing problem! But i don't have any idea where to start searching!

The scene hast 7 lights in it!

sun light from front right. (directional light, raytrace shadows )
back light from back left. (spot light, raytrace shadows)
fill light from front left (spot light, raytrace shadows)
and 4 ground lights on the floor (Ambient Lights)

Also this picture is rendered with Mental Ray and Final Gathering!

Thanks to you all

Greetings Braggart

[mitchbraggart]

Seriously i need help here!

Couldn't figure that problem out by myself!

Anybody got an idea where to start?

Have a nice weekend!

Greetings Braggart

[jeanmarc]

As you can see, you haven't had any replies in 5-6 days.  Why?  You might ask.

Most people who read this stuff will be glad to help, but they're busy and you need to make it easy for them to respond.  So, let's change your initial posting a bit.

1) When you post a problem "not rendered right" is not something anyone can focus on.  Post, in a more descriptive style, precisely what you are seeing that creates the impression of "not rendered right" in your mind.  Picture what it should look like, describe it, and what looks different from what 'it should' look like to you, THEN help will be on its way.

2) What kind of surface shaders (with settings) are you using where you see "not rendered right?"

3) What kind of lights (light shaders with settings) are you using?

Do these things and you will get help faster.

...

Now, my first question, not knowing any of the above, is WHY are you using so many lights with final gather?  Are you using an image to assist with the lighting (HDR or ???)

• Jimbo

[mitchbraggart]

Ok sorry for the lack of information here. I try to be more specific!

So here is the picture:

As you can see the shadow in the blue circle forms a triangle pattern! In my oppinion this is rendered wrong! I can't think of any reason why the shadow should form such an straight forward triangle pattern.

Settings:

I use a lambert shader on the shirt.

diffuse:0.6
translucence: 0
translucence depth:0
translucence Focus:0

in the color channel i have a Tiff File with alpha channel applied.
also i applied a Tiff file to the bump channel.

The background is a lambert shader with a ramp applied to the color channel

BG shader has a a little ambient color and incadescence.

There is one directional light in this scene with standard raytraced shadows.

The Light does not affect the background.

The Maya default Light setup is turned off.

Also standard final gathering is turned on.

Any idea why this is happening?

If more information is needed please inform me!

have a nice week

Braggart

[carles-piles]

In my oppinion it's just that the directional light is casting the real geometry in there because it is hard too much.

You can kill that undesired result by increasing the value for "Light Angle" that you can find in the Raytrace Shadow Attributes tab (0.00 by default).

It will make your shadows softer (according the amount) so also more realistic.
If you are using values higher than zero, you have to increase also the value for "Shadows Rays" (try 8, or 16, or 32, etc. until the noise is gone, depending on how much angle you've entered).

The last box, Ray Depth Limit is the amount of times that the shadow is computed for reflection/refraction. So, if you put a reflective sphere in scene, by default you will see that is not casting its own shadow. You need to increase the depth in order to get at least the first bounce.
Be careful with that parameter, values higher than 2 can increase drastically the rendering time if you have many reflective objects in scene.

Hope it helps.
Cheers,
Carles

[mitchbraggart]

@ Carles Piles

Hi Carles,

of course i agree with you in that point. But thats not really the problem.

I sure know that raytraced shadow in their default settings produce hard shadows, but i don't understand why they form such triangle pattern where only a straight shadow line shoud appear.

I already played with some raytrace settings to smooth out the hard eges but the triangles won't go away completely.

When i alter the position of the light i get different pattern, but they are always blocky and not like a clean hard shadow edge.

Greetings Braggart

[mitchbraggart]

Fixed that Problem

I discovered that the shader for the shirt had some translucece.

I did not notice that. thought i turned that off.

Sorry for the trouble! Thx everybody who tried to help!

Greetings Braggart