Translucence in Principal Shader
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- VTL
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- robsdesign
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Hi, you could try a very high refraction roughness but to do that on the Principled Shader means increasing the reflection roughness as they decided to link the two values.
The Classic Shader has a translucent refraction model and the refraction roughness is not tied to reflection. You may want to try both methods to compare results and render times. (Both methods tend to produce a lot of noise)
Rob
The Classic Shader has a translucent refraction model and the refraction roughness is not tied to reflection. You may want to try both methods to compare results and render times. (Both methods tend to produce a lot of noise)
Rob
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- jsmack
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Translucence is too broad of a term, do you mean subsurface scattering or blurry refraction? Refraction is under ‘transmission’ and subsurface scattering is ‘subsurface’ with two different modes single scatter and full scatter. The first being a fast single scatter, the second being based on the diffusion (infinite plane) model.
For the old diffuse based ‘translucent’ bsdf from the classic shader, this is missing in the principled shader. You can try increasing roughness to 1, but it's not the same. You will have to build a shader by hand. I have attached a screenshot of an example ‘translucent’ shader in the vein of the classic shader.
For the old diffuse based ‘translucent’ bsdf from the classic shader, this is missing in the principled shader. You can try increasing roughness to 1, but it's not the same. You will have to build a shader by hand. I have attached a screenshot of an example ‘translucent’ shader in the vein of the classic shader.
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- VTL
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- ProceduralFrankie
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- jsmack
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FrancescoVerboso
Hello!
Sorry if i dig up this topic but i am very interested, so i am very new into shading in houdini and tryed your nodes but it comes out black, i am defintely missing something. Would you mind attaching a scene file or tell me how to preceed?
Many thanks
Francesco
It's not visible in my node graph, but the label for the transmissive diffuse is ‘refract’ instead of ‘diffuse’, and shade both sides as front is disabled.
For a brighter/glowier look, disable ‘vm_smoothP’ on the object. This might result in a rough terminator for low poly shapes, but it should be fine for subD and high-poly meshes.
To render closed shapes properly, secondary bounces for refraction must be greater than 0.
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- Snackovich
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Great thread! Thanks for sharing jsmack, inspired me to try some rendering too…
The fully translucent image above is wonderful. Did you use that same shader?
And can you share any tips on render settings? To remove a lot of the noise for the image below I had:
pixel samples - 8x8
min ray samples - 2
global quality - 4 (probably should have just kept increasing the refraction quality instead)
refraction quality - 5
refract limit - 15 (not sure this was necessary)
But these seem pretty high, render time at 720p was just under 1.5 hours.
attached is the scene file too for anyone unsure about the material network above.
The fully translucent image above is wonderful. Did you use that same shader?
And can you share any tips on render settings? To remove a lot of the noise for the image below I had:
pixel samples - 8x8
min ray samples - 2
global quality - 4 (probably should have just kept increasing the refraction quality instead)
refraction quality - 5
refract limit - 15 (not sure this was necessary)
But these seem pretty high, render time at 720p was just under 1.5 hours.
attached is the scene file too for anyone unsure about the material network above.
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- ProceduralFrankie
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- jsmack
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The shell rendered in about 30 minutes on my quad core cpu.
@Snackovich, those numbers do seem a bit high, but you do have depth of field enabled. Is your material a glossy refraction, or translucence(diffuse refraction) like in my scene? For glossy refraction (ggx principled shader) I find it requires very high samples to eliminate noise, leading to some long render times, but a global quality of 4 and refract of 5 seem quite high. The refract limit is probably excessive. For glossies I would tend to keep it lower, 2-3, as the subsequent bounces are more and more diffused.
@Snackovich, those numbers do seem a bit high, but you do have depth of field enabled. Is your material a glossy refraction, or translucence(diffuse refraction) like in my scene? For glossy refraction (ggx principled shader) I find it requires very high samples to eliminate noise, leading to some long render times, but a global quality of 4 and refract of 5 seem quite high. The refract limit is probably excessive. For glossies I would tend to keep it lower, 2-3, as the subsequent bounces are more and more diffused.
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