Trying to recreate a simple Poser candleflame shader in ShaderMixer (3Delight)

Richard Haseltine

It's been a while sionce I have doen even the most perfunctory shader mixing, but I've put a link on the desktop to try to have a look by-and-by if no one more comptenent beats me to it.

3dcheapskate

Thanks Richard.

When I look at those three nested ellipsoids I see a horizontal (side-to-side) variation between edge and centre that is dependent on the height up the flame, same as before.
To me an Edge Blend is still the obvious way to deal with the former, although a comparison of X and Z camera-space* normals is an option, but then that's part of what an Edge Blend does anyway.
V texture coordinate is similarly the obvious way to deal with the latter because of my cylindrical mapping, althogh the vertical component of the world-space surface normals is another option. From bottom to top of the flame neither of these vary in a linear manner, but both vary in accordance with simple trig functions.

So I think I'll try the same approach as I did in Poser, ignoring both the colours of the flame and the transparency, and just trying to get nested black and grey ellipsois within a white ellipsoid.

Firstly, just a simple Edge Blend:

 

Then just the V coordinate (inverted so 0 is at the bottom):

 

And then applying gain to that inverted V:

 

Looking at those, I'm sure that I should be able to create what I'm after.

 

*An Edge Blend effectively takes the component of the camera-space surface normal that's pointing directly at the camera to determine how 'head-on' the surface is. A normal being a unit vector, the value should be cos(α) where α= 0° for head-on, to α=90° for edge-on.

3dcheapskate

Just playing, using the screenshots in the above post as reference. Note: I'm sometimes applying non-white colours to the edge blend simply to insure that clicking the 'Apply' button has actually applied the shader:

 

The one below is on the right track I think:

 

...although significantly different from what I got in Poser

 

(Having successfully reproduced my Poser Firefly render in Poser Superfly by playing with a separate EdgeBlend node in this way, I thought it was worth another go for 3Delight)

3dcheapskate

...and just when I thought I was starting to make progress, I run into a completely different problem when applying that to the transparency/opacity (spot render in the viewport)

  

Richard Haseltine

I can't see that it would matter, since there appear to be no ray-trace operations in the shader, but on the opacity have you tried increasing the ray trace depth in Render Settings?

3dcheapskate

I didn't try that - I just added the DS Default Material brick back in and the problem disappeared.

 

Just to be absolutely sure that was the cause I bypassed the DS default brick again. Sure enough, problem reappeared. I hadn't noticed before, but the problem shows up even on the candle wick. I think I'll just pretend that I never saw this problem:

 

And just as a visual reminder, here's the output of the Edge Blend brick that I plan to use to control the opacity, plugged into the ambient colour of the DS default with zero transparency just to help visualize

 

Next step, try to get the black-orange-yellow-white colour stuff working.

 

(I've attached the DBM including the connected DS default material, zipped. Note that it also contains the rest of the ongoing version of theshader with various connections removed, so it's a mess)

 

3dcheapskate

Why not try using that Edge Blend to control the three Mix bricks I was using before to try and do what the Poser ColorRamp was doing ?

 

That's sort of okay-ish I guess ? So I've zipped the DBM and attached that. At least I think I'm now on the right track.

 

Edit (15th June 2022): I think I'm going to give up on this.