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Light and shadow
Posted: 31 October 2012 06:53 AM   [ Ignore ]
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Hello guys,

Here is my problem :

- I have a scene with one character, under this character i have a plane.
- I use pwCatch to hide plan and catch only shadow.
- I have 2 distant lights

I want to catch shadow on my plane only from 1 distant light ... do you have any idea?

Thanks for your help !

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Posted: 31 October 2012 07:03 AM   [ Ignore ]   [ # 1 ]
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Switch the shadow off the light you dont want. OR use a point light with the fall off set low enough that the light doesnt hit the plane.

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Posted: 31 October 2012 07:35 AM   [ Ignore ]   [ # 2 ]
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Thanks for your help but ... i can’t ...

Distant light 1 : shadow on character but not on plane
Distant light 2 : shadow on plane but not on my character

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Posted: 31 October 2012 07:48 AM   [ Ignore ]   [ # 3 ]
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have you tried using spot lights instead of distant lights?

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Posted: 31 October 2012 07:56 AM   [ Ignore ]   [ # 4 ]
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I can change only the distant light 2 because the distant ligth 1 is from sky of terra

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Posted: 31 October 2012 12:40 PM   [ Ignore ]   [ # 5 ]
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I have tried everything i could imagine but i can’t solve my problem… to resume i need to catch shadow on primitive from specific light ...

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Posted: 31 October 2012 01:07 PM   [ Ignore ]   [ # 6 ]
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What exactly are you trying to achieve?

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Posted: 31 October 2012 02:24 PM   [ Ignore ]   [ # 7 ]
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I have a character on a plane. I have 2 distant light (one from SKIES OF TERRA) http://www.daz3d.com/shop/skies-of-terra-volume-one  and an other one.

The distant light from SKIES OF TERRA is named “sun” the other one is named “Distant Light 2”.

What i need :

- The light “sun” must illuminate my character with shadow BUT i don’t want to see shadow on my primitive plane from this light.
- The light “Distant Light 2” must not illuminate my character BUT i want to see shadow on my primitive plane from this light.

As i’m not a native English speaker maybe i’m not clear enough sometimes, whatever thanks for your help.

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Posted: 31 October 2012 02:46 PM   [ Ignore ]   [ # 8 ]
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tankeratl - 31 October 2012 02:24 PM

What i need :

- The light “sun” must illuminate my character with shadow BUT i don’t want to see shadow on my primitive plane from this light.
- The light “Distant Light 2” must not illuminate my character BUT i want to see shadow on my primitive plane from this light.

As i’m not a native English speaker maybe i’m not clear enough sometimes, whatever thanks for your help.

First of all, if these are the only 2 lights in your scene then I strongly suspect that the shadows are going to look fake. I’m assuming that you want to position 1 light so that the shadows on the plane point a certain direction but you don’t like the way that looks on the character and so you’re using a second light for that. If that’s what you’re doing then like I said, it’s probably going to look off since the shadows on the character will be going in 1 direction but the shadows on the ground will go another way.

That said, your best bet is to do this in post processing. Create 1 render for each light and then layer them in a program like Photoshop or the GIMP. I can go into more detail on how to blend the 2 images if you need more help.

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Posted: 31 October 2012 02:56 PM   [ Ignore ]   [ # 9 ]
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Thanks adacey,

This is not correct. I know there is a way with photoshop but if i could do this in daz3D it would save me a lot of work ...

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Posted: 31 October 2012 03:18 PM   [ Ignore ]   [ # 10 ]
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tankeratl - 31 October 2012 02:56 PM

Thanks adacey,

This is not correct. I know there is a way with photoshop but if i could do this in daz3D it would save me a lot of work ...

The controls for distant lights only give you no shadows, deep shadow map or ray traced shadows, there’s no settings for which objects do or don’t cast shadows. I don’t know of any surface shaders that add this feature either, but maybe there is something out there.

If you setup the render for each light properly then your post work should simply be layering them. See this technique for details on how to do it. Make sure anything you don’t want to see on a given layer is black. Anything that’s black will be invisible when using the screen blending mode.

What I’d do is turn off the sun light and the primitive plane and set the background to black. Turn off anything else that you don’t want lit by the sun light either.

Then, turn on the sun light and the plane and turn off distant light 2. Set all of your character’s surfaces to be black and the same for anything else you don’t want to look lit from this light.

That will be a bit of work with turning things on and off in DAZ and adjusting surfaces but, then when you setup the layers in Photoshop and set the blend modes to screen you won’t have to do any masking.

Depending on what else you need for achieving your lighting you might need to add separate renders with shadows turned off, or the lights set to diffuse only or specular only to give you the effects you want. Again, just remember that anything you don’t want should be set to be black and then you won’t have to mask it out.

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Posted: 31 October 2012 04:08 PM   [ Ignore ]   [ # 11 ]
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For the Skys of Terra lighting Open the UBER light set find the SUN setting and set it to NO Shadows. All Uber Envro Light sets do have a LIGHT that you can set different than the default setting. Even the Shadow settings.

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Posted: 31 October 2012 04:20 PM   [ Ignore ]   [ # 12 ]
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THANKS Jaderail !! It was so easy !!! With some adjustments on my other ligth the render is perfect.

Tanks again to everybody i really appreciate your help.

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Posted: 31 October 2012 04:22 PM   [ Ignore ]   [ # 13 ]
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Layering the two renders shouldn’t need any fiddling with materials - render with the plane and the Distant Light 2, but with the Skies of Terra light off, then save it; delete the plane and distant light 2, turn on Skies of Terra, render and save as tiff or png; now if you load the PNG in Photoshop it should have no background, so you can just drop it on top of the other render and it should be what you want (hold shift down when tou rag from the PNG into the render with background, to make sure it stays in registration).

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Posted: 31 October 2012 05:18 PM   [ Ignore ]   [ # 14 ]
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Jaderail - 31 October 2012 04:08 PM

For the Skys of Terra lighting Open the UBER light set find the SUN setting and set it to NO Shadows. All Uber Envro Light sets do have a LIGHT that you can set different than the default setting. Even the Shadow settings.

Wouldn’t that mean that the light casts no shadows? It sounds like it fixed the OP’s issue so maybe I misunderstood what he was trying to do since I thought he said he needed the sun to still cast shadows on the character. I don’t have the Skies of Terra product so maybe I’m missing something.

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Posted: 31 October 2012 05:23 PM   [ Ignore ]   [ # 15 ]
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Richard Haseltine - 31 October 2012 04:22 PM

Layering the two renders shouldn’t need any fiddling with materials - render with the plane and the Distant Light 2, but with the Skies of Terra light off, then save it; delete the plane and distant light 2, turn on Skies of Terra, render and save as tiff or png; now if you load the PNG in Photoshop it should have no background, so you can just drop it on top of the other render and it should be what you want (hold shift down when tou rag from the PNG into the render with background, to make sure it stays in registration).

The technique I’d mentioned assumes that you’d be actually mixing the lighting from 2 renders, not just using transparency.

When I tried it with transparency before I found that the edges weren’t great, very jagged and pixelated (not anti-aliased). Using black for things you don’t want (background, or a material that you don’t want hit by a certain light) and the screen blending mode will literally make it invisible, but the edges will be as soft or hard as the shadows are, which I found blended better. Plus, it allows you to overlay the effects of 2 lights on the same area whereas simply stacking them would mean you’d have 1 or the other.

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