Hello :-D
I'm trying to render a realistic glass window pane using the principle shader. Yet I can't manage to get a transparent result with reflections and without refraction, because the glass in a window hardly refracts. The way I understand it is that the IOR is driving both specular and refraction intensity. So it's refraction and reflection or none, or am I missing something?
What is the best way to do this?
I used to work with Houdini up to version 13, but didn't use Houdini for 10 years. (I was know as Nerox or Nick Nimble, but couldn't access the old account anymore). I tried to get up to speed by watching lots of YouTube videos. I still have to get used to all the new stuff. What am I missing?
ps
Bonus question
How do I get the extra image planes like refract and reflect to work in IPR? It seems they should be there by default, but they do not show up. When I add an extra image plane by hand with the vex variable: reflect, it remains black.
Render a glass window pane with the principle shader
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- bravon
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- Joined: April 2023
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- bravon
- Member
- 2 posts
- Joined: April 2023
- Offline
I've figured it out 
In short the solution that I found uses coat reflectivity instead of the normal reflectivity, because the coat is not linked to the refraction parameter. How ever I needed to unlock the shader and tweak a few things inside in order to get a sharp reflective transparant window surface without refraction.
This is how I did it:
On the principle shader set
- Opacity/fake caustics: enabled
- Surface/specular: IOR to 1, Roughness to 0
- Surface/reflectivity: Reflectivity to 0, Coat to 1
- Surface/transparency: Transparency to 1
Right click on principle shader and Allow editing of contents, dive in, search for: principledshadercore1, right click and allow editing of contents and dive in. Search for a node called: coat_reflection. On this node set index of refraction to 10
and refraction to 0. On the rough input there is a node called: fit2, disable it.
Now you should have a shader that has the characteristics I described above. Enjoy :-D

In short the solution that I found uses coat reflectivity instead of the normal reflectivity, because the coat is not linked to the refraction parameter. How ever I needed to unlock the shader and tweak a few things inside in order to get a sharp reflective transparant window surface without refraction.
This is how I did it:
On the principle shader set
- Opacity/fake caustics: enabled
- Surface/specular: IOR to 1, Roughness to 0
- Surface/reflectivity: Reflectivity to 0, Coat to 1
- Surface/transparency: Transparency to 1
Right click on principle shader and Allow editing of contents, dive in, search for: principledshadercore1, right click and allow editing of contents and dive in. Search for a node called: coat_reflection. On this node set index of refraction to 10
and refraction to 0. On the rough input there is a node called: fit2, disable it.
Now you should have a shader that has the characteristics I described above. Enjoy :-D
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