Redshift light as mesh conundrum


So I’m working on an animation where I have a light strip that I want to have “fill” from one end to the other as an object powers up and I’m using a mesh light so it interacts with Redshift Environment fog. Problem I’m having is I have no way to control the filling as a mesh light. Is there a way to attach a field object to, say, the light intensity that I’m unaware of?


For a cylindrical pipe like that I might just be tempted to dupe the geometry. copy A being the light, copy B not. And just grow a sweep to swap from one to the other.

I had a little play and here’s a possibility I think:
Just make sure your pipe has decent UV’s:

RSstate outputs 0 to 1 based on UV co-ordinates. Vector to scalar. That is modulated through a step ramp. Animate the ramp and you should be good to go.


Thanks Mike

I see what you’re saying, problem being we like to model in Medium and Zbrush cuz fun and I could rebuild those in c4d and sweep like you said but I’d rather workout a solution like this that can adapt to any geometry.

All of those nodes you show I have not touched yet but was planning on looking into :). Was hoping it was a simpler solution that I was overlooking.

What I wound up doing for now (but I’m definitely going to build your approach) is used a Vertex map again tied to a posemorph set to maps and a field and used that to morph between an unlit and an incandescent material. You don’t get the nice volumetric glow but the initial effect is there.


Here’s the file if you want to play : )

mesh light UV.c4d (234.6 KB)

excuse the c**p quality - wasn’t intended for public consumption : )


Thanks man, I really appreciate it!


Ahh, that’s what the physical light node does! Neat! :slight_smile:


Hey Troyan,
I was just playing with this idea - and I realised I’d actually overthought it. You don’t actually need Rs state and the vector to scalar. The ramp - make sure it’s set to UV, directly into the light node will do.

You can do some fun / useful stuff piping ramps into the intensity and / or colour input , and animating the UV’s… : )


I think you’re having a little fun with this :slight_smile:

Yep, you’re right! I was just dissecting this when you posted, trying to understand what those nodes did :). That’s going to be fun to explore, especially for how simple a setup it is.

The Redshift manual is pretty confusing to look stuff up in, tried looking up the Physical Light node. You’d think the information would be more comprehensive.

Is that the purpose of the Physical Light node? To basically turn objects into light sources?

Also, the ramp. Have not used them yet but obviously powerful. Why is there no gradient between the light and dark knots? Is there a way to add a little soft falloff at the edge in the ramp settings?


Oh, never mind, I found it. Interpolation of the knots.


super cool solution. Troyan–was also gonna say you could use the post bloom effect in RS to get that glow using just the emmissive material without need for volumes. But this is great.


Hmmm, need to look into that bloom. This is a great solution with lights, the only problem being the limitation on the volume contribution for individual lights. We’re spoiled from C4D’s build in volumetric lighting :).


Joel, are you talking about the bloom effect on the camera? Love the bloom but it applies to the image overall where I’d like to be able to tie it to just the areas that have a certain material/light/effect. Unless I’m misunderstanding?


Totally agree on the documentation, it’s sorely lacking IMO. I’ve been using Rs for a while and I’ve had to write my own notes on quite a lot of stuff that isn’t explained well.

The Physical light node won’t turn anything into a light - it’s purely for control of physical lights via the shader graph. Basically what we’re doing with it now.


Thanks Mike, I figured that after playing a while longer. Need to tweak our UV’s but that’s a pretty cool solution, thanks for that! :slight_smile:


Yes Troyan. And what you are saying is true–it does apply to the image, In my experience it tends to lock on to the brightest elelement in the frame and sometimes it just works. Thought it would have been worth a try. Doesnt take much to activate it and fiddle with the settings.


Yeah, it’s a great solution for sure, problem here is the probe body is white, so it basically blooms the whole thing and fiddling with the tolerance etc. doesn’t really choke it out enough for the glows to be prominent. I would say 99% of the time, bloom is a great solution for this.


Apparently if you have the Houdini plugin, you can use their COPS node to assign post fx, including bloom, to render on specific materials only and not the entire image. Pretty slick. Hopefully going to test that out in the morning.