Skybox "no shadows cast&recieve"


(Dark Minaz) #1

Hi there

In my latest model i was trying to add a skybox

Now the problem is, that even one sided it recieves shadows, and casts shadows.
So what i am looking for is something like
setAttr "pCubeShape1.castsShadows" 0;
setAttr "pCubeShape1.receiveShadows" 0;

or

Or even the option to just have a certain material not recieve shadows
like
setAttr "lambert1.receiveShadows" 0;

Is there a way to do that in sketchfab?
According to all the tutorials etc that i could find, the only option was to set it to shadeless, and that would hurt my scene more than it would help.

Link to the model.

4 Troopers Try 3 by dark-minaz on Sketchfab


(Paul Sketch) #2

Single face should do the trick to prevent the "skybox" from casting shadow. (seems the case here)

On the Receiving side, a trick is to try to enable a small transparency alpha blend on a material to make it not receive "shadow" either. but at the cost of performance (alphablend is costly)
(note that it also disable cast),

There is no current way to disable/enable shadow per material explicitly in sketchfab.


(Dark Minaz) #3

okay, thanks

Well it still seems like it does take some of the light, the emission did help a bit.
Ill try out the alpha blend, didn't seem to work before.

Nope, emission is on, transparency is on alpha blend with 10%

Guess for the final version ill try out with and without and see how much it affects the light then. This one just seemed way darker.

added the same light (ditch river with 2,2) on both, so you can clearly see, the one sided doesn't stop it from getting affected.


(Stephomi) #4

Using a geometry skybox has many disadvantages currently in sketchfab.
Ideally, it should be uploaded as an hdri environment, a feature we are currently working on.

  • Removes the albedo texture (set the slider to 0)
  • Set the emissive texture to 10
  • Put a 1x1 black texture in the AO channel and check Occlude specular
  • Disables the alpha blend, with the above trick it shouldn't be necessary

See comment below for more explanation :
https://sketchfab.com/models/a4cb3debb11643a6978e5c82cd439600
So basically, you'll still have ponctual light fresnel reflection though but it should be barerly noticeable on your model


(Paul Sketch) #5

Note that "opting out of Shadow" doesn't mean you opt out of lighting, the single face and alpha blend trick is for shadow, not for light.

What you're looking for is opting out of "lighting", and for that @stephomi steps are your best bet.


(Dark Minaz) #6

ah yeah, i am kinda just wanting it there as a cool background that moves with the scene in the end.

But thanks @stephomi
Like that it looks decent (no shadow artifacts on the box), so i just have to make the light slightly stronger.