Baking Everything Behind Transparent Materilal into Diffuse?
polycounter lvl 6
Hello.
I've recently come across a scenario where I need to create a game asset with a semi-transparent material with visible wiring underneath.
This wiring isn't deep enough down for very noticeable parallax so I could save on performance by not putting any geometry below the transparent material and instead of having it transparent I could just bake the light from the wires that shines through it into a diffuse map.
The problem is I'm not sure what application can achieve this. There is the simple way of creating the texture of the wires then slap it onto the transparent material and apply blur and such (which I was planning on doing), but I can only fake so much this way. I can't create refraction or bounced lighting or whatever when all I have is the image.
I believe my best bet would be with Unreal Engine, making use of some transparent materials and rendering a camera's view to texture. But this would be pretty tedious to set up. I'm wondering if anyone has any ideas on how this could be achieved a little more easily, with something like 3ds max as I can't find a way of doing it.
Ideally I'd want good control over the transparent material e.g. how much it blurs stuff behind it, how much it refracts and so on. I can't see any options for that kind of stuff in a standard max material, or even how to bake the background onto the plane in the first place.
Thanks for any help.
I've recently come across a scenario where I need to create a game asset with a semi-transparent material with visible wiring underneath.
This wiring isn't deep enough down for very noticeable parallax so I could save on performance by not putting any geometry below the transparent material and instead of having it transparent I could just bake the light from the wires that shines through it into a diffuse map.
The problem is I'm not sure what application can achieve this. There is the simple way of creating the texture of the wires then slap it onto the transparent material and apply blur and such (which I was planning on doing), but I can only fake so much this way. I can't create refraction or bounced lighting or whatever when all I have is the image.
I believe my best bet would be with Unreal Engine, making use of some transparent materials and rendering a camera's view to texture. But this would be pretty tedious to set up. I'm wondering if anyone has any ideas on how this could be achieved a little more easily, with something like 3ds max as I can't find a way of doing it.
Ideally I'd want good control over the transparent material e.g. how much it blurs stuff behind it, how much it refracts and so on. I can't see any options for that kind of stuff in a standard max material, or even how to bake the background onto the plane in the first place.
Thanks for any help.
Replies
https://www.google.com/search?q=parallax+cubemap+interior+unreal
I can't show my ref, but the image I made describes fully what I'm aiming for. I have a transparent material (in this case window), behind it some details (in this case a landscape) and I want what appears through the window to be baked down into a texture, so there's no transparency required for the landscape to appear on the window.
I'm interested in achieving this through some kind of rendering/baking, not texture manipulation and filters.
Something like rubber or thin plastic that can let some light through and have similar effects to subsurface scattering. How could I bake the lighting created by these objects into a diffuse?
I have a feeling UE could do most of this.
good luck
I'm pretty sure again, that's unrelated to what I want.
@Eric Chadwick
That just might be the simple solution I need. Though these textures need to be made for complex unwrapped assets, meaning I need the camera to be orthographic and positioned to capture the entire plane and no more or less. That would be really tricky to just eyeball it and get it perfect, not sure if you know of any way to set this up automatically?
I could definitely set up a camera to render this for me like you mentioned. I just need the right camera settings to capture the full plane.
http://wiki.polycount.com/wiki/Texture_Baking#Transparency
No offence, but did you actually read it ?
I know you said you don't want realtime effects, but maybe the examples in here can give you some ideas anyway: https://simonschreibt.de/gat/windows-ac-row-ininite/
One thing i think would help sell the effect is using a simple shader for some fresnel effect: the more you look at the glass from the front, the more you should see the cables. The more you look at it from a grazing angle, the more it should look like a blurry reflection of the environment (from a cubemap or spheremap etc.).
It's not an expensive effect as long as you keep it as simple as described.
@poopipe
Not the first time people come with solutions without reading a post, I read your query and it wasn't related. I want lighting, refraction and properties of glass baked into a diffuse as if I were to look through it and capture what I see, I don't want the actual alpha maps. Even there is some kind of info on this topic there, it's not related to my software. No offence.
Anyway this has already been solved with a top-down camera setup, I can customise the transparent material to my liking to get desired effects. At this current stage it looks more like a warped texture but it's just a quick test.
https://www.dropbox.com/s/7etik2vx4hnr045/windowTest.mp4?dl=0
I just mocked up that shader in Unity, it's CG, so with a few tweaks it should migrate into Maya's CGFX fairly easily. It's not an ideal solution for an offline renderer though, would that be it's use case? Also like I said, it's not a baking solution, it requires both a foreground image for the window frame and a background image for the information behind it. I could get it to work in Unity with render textures quite easily though, not sure about doing that kind of stuff in Maya...
Edit:
Full disclosure I only read the first few posts
I guess the method I'm more after would better be applied to something that isn't flat. Here's a good example I found. The black on the far left can be seen through semi-transparent rubber. This is more along the lines where baking lighting of transparent objects would better used than in my current case. But even this could be fairly easy replicated with texturing with a simple gradient.
You could probably bake the SSS to a diffuse through Arnold or something but I don't trust their baking tools, it's something you may have to custom write. Such unique tools probably don't exist because it's they're for very small cases and don't really come up a lot, and are easy to fake with a little manual work.
The way your first example gets rendered is completely different to this new one with sub-surface scattering. Light transmittance doesn't physically colour the material it is transmitting through, it just distorts the light from source. Most renderers render physically so it's not like they're mapping lighting to surfaces and rendering that, they're literally firing photons through the scene.
that's a no then..
I'm out.