Multiple Atmosphere Objects

[DaJuice]

I'm wondering if someone has experience with this situation and maybe some tips. It seems strange stuff happens when you have more than one atmosphere object in the scene, mainly they don't combine too well. For example, here you can see two i3d "clouds" touching at the ends. The yellow one has a density of 10 while the pink one has a density of 1, yet you can see the pink cloud right through its yellow sibling, as if it had x-ray on or something.

Here's an animation of the same thing, you can see the effect better. I don't know what codec is popular so here's 3 of them! Right click > Save...

http://www.geocities.com/stehrani3d/3dfile...g_objs_3ivx.zip

http://www.geocities.com/stehrani3d/3dfile...g_objs_DivX.zip

http://www.geocities.com/stehrani3d/3dfile...g_objs_Xvid.zip

The scene file if anyone wants to fiddle

http://www.geocities.com/stehrani3d/3dfile..._atmosphere.zip

I've tried combining fog shaders in VOPs as well, but the results have not been good.

Cheers

[lisux]

I'm wondering if someone has experience with this situation and maybe some tips. It seems strange stuff happens when you have more than one atmosphere object in the scene, mainly they don't combine too well. For example, here you can see two i3d "clouds" touching at the ends. The yellow one has a density of 10 while the pink one has a density of 1, yet you can see the pink cloud right through its yellow sibling, as if it had x-ray on or something.

I've get some problems with atmosphere objects too.

If i've an atmosphere object that overlaps with a geometry object, the geometry object doesn't allow to render the atmosphere object.

For example, i have an atmosphere object wich has his origin in the world origin, if a geometry object covers it, but the atmosphere object occupies an area over the geometry object, so theorically i would have to see the atmosphere over the geometry, but it doesn't.

It seems that if a geometry object covers the origin of an atmosphere object, the atmosphere it doesnt rendered, although the atmosphere overlaps over the geometry.

Any clues, thanks.

[sibarrick]

Yeah atmosphere objects seem to render in the order they were created (it's been a while since I did this though) so to get the pink one behind the yellow one try creating them so that if you view them in list mode - user defined list order - they are the other way round to what you have now.

Other than that I think you will have to do it in two passes. If you want them to totally interact I think you will probably have to do that in vex land.

[DaJuice]

Hmm, I haven't encountered that one lisux. I'll have to try that.

Thanks Simon, I suppose I will have to do something in vops. I've tried different ways of combining 2 fog shaders (I just right click on the shop>create new vop type) and the only one that looks correct is adding them together. But it has the side effect of blowing out the rest of the scene. Hmm, maybe if I render it as a seperate pass it won't do that.

[lisux]

Hmm, I haven't encountered that one lisux. I'll have to try that.

Thanks Simon, I suppose I will have to do something in vops. I've tried different ways of combining 2 fog shaders (I just right click on the shop>create new vop type) and the only one that looks correct is adding them together. But it has the side effect of blowing out the rest of the scene. Hmm, maybe if I render it as a seperate pass it won't do that.

15767[/snapback]

Hi DaJuice, i've made an image3d shader that solves the problem of compositing different atmospheres.

This atmosphere shader stores the P, or Pz if you pass to the shader your render camera origin, attribute of your more density point in the 3d texture.

So i use an atmosphere shader that uses the channel that stored this z buffer information and exports it to make it available to deep rasters, so you can only need to save this information in the P or Pz plane and then use a z Composite COP to compose them together.

Cheeers

[doc]

Yeah atmosphere objects seem to render in the order they were created (it's been a while since I did this though) so to get the pink one behind the yellow one try creating them so that if you view them in list mode - user defined list order - they are the other way round to what you have now.

Other than that I think you will have to do it in two passes. If you want them to totally interact I think you will probably have to do that in vex land.

15752[/snapback]

to do it in vex you'll need to modify the vex 3dtexture fog

shader so that it computes the density of multiple i3d images.

my 2 cents

Luca

[DaJuice]

lisux, sounds good but to be honest I don't know how to implement that.

I hope SESI will fix this in the future.