baking shadows

EmmaMaybe

EmmaMaybe

0
baking shadows

/waves hi,

Apologies if this has been asked before, searched but couldn't find it.
I'm in the middle of making things to import into second life, cheetah and me are really becoming friend, have fun together with the materials, unwrapping uvmaps and all those fancyness. But now i'm trying to bake shadows of my models on a plane underneath it. I need/want the texture for that plane to be transparent with only the shadow on it.
I tried a lot of things, the shadowmat too, but so far the only thing i get is either a black/dark square or nothing at all.
Can someone explain or give me some directions on how to do this?
 
Here´s a basic set-up.
You might need to know how to set the camera background color to zero%, enable shadow+trans at a light source and to adjust the "white point" at the Shadow-mat material.

Cheers
Frank
 

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  • BasicShadowBake.png
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Thank you for your quick reply.
The way second life works for me is, i upload the model as .dae separate from the textures. So i would like to place (for example) a chair on a plane, much like your example, and get a baked transparant texture of that plane with just the shadow, not so much trying to get a flat render of the whole scene.
 
EmmaMaybe said:
Thank you for your quick reply.
The way second life works for me is, i upload the model as .dae separate from the textures. So i would like to place (for example) a chair on a plane, much like your example, and get a baked transparant texture of that plane with just the shadow, not so much trying to get a flat render of the whole scene.
Click to expand...

Not sure why you even need to think about baking shadows into SecondLife textures any more. – I mean, that was OK for the old lighting model, but with the advanced SL lighting model with AO and shadows turned on, pre-shaded textures will both overcompensate the viewer generated shadows, and be completely wrong in terms of the sun/moon generated shadows throughout the SL day, but also in terms of point lights placed in the scene by other builders.

Now, with the new lighting model, I actually would not buy pre-shaded objects and textures any more.
 
i do agree with you about the advanced lighting/shadow/materials however not all people are able to use these. While we could have a conversation about this, it comes down to taste.
So im not asking if i should, i just really want to know if i can use cheetah3d for this and how
 
EmmaMaybe said:
..still trying. but suddenly i'm wondering can you even have transparency when baking textures?
Click to expand...
We can - but what you need is a transparent camera background and that case won´t work, because the rays won´t hit any surface/object - so the rendered
shadow will be end in an black image. You´ll notice how the irradiance cache tries to record any rays but failed, when radiosity is enabled and the rendering process slows down:
How precise do the shadow has to be? Can´t you just fake it?
You can render the shadow onto a white plane - save to PNG and get rid of the "white" in post with PS or Preview.app or GIMP or else.

Cheers
Frank
 

Attachments

  • ShadowMapTransBaking.png
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i tried your tip with the white plane, the result is very pretty even if it is far more work than i expected or hoped for :p

just for my understanding, it seems to me with transparent camera background you're not referring to giving 0% opaque black colour to the camera tag and using the hdri tag (with bg checked off). but then, what dó you mean?
 
EmmaMaybe said:
i tried your tip with the white plane, the result is very pretty even if it is far more work than i expected or hoped for :p

just for my understanding, it seems to me with transparent camera background you're not referring to giving 0% opaque black colour to the camera tag and using the hdri tag (with bg checked off). but then, what dó you mean?
Click to expand...

Click on the background color for the camera then use the opacity slider in the color picker.

​
 

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