Hi guys,

I'm very brand new to this community and to this amazing software, other than being a newby in the 3D graphics field.

Some months ago, I started studying Blender, which seems to me to be a great software. For some reasons I approached to Houdini and wanted to make the very same model I've realized with Blender also with it. It is attached.

My model is a simple laboratory couple of vials of plexiglass with some liquid inside. As you can see, with Blender I've managed to do two great (for me) things, that I'm not able to replicate with Houdini:

1) thick surfaces (In blender it exists the “solidify” function that makes primitives thicker automatically);

2) the effect of curved plastic, darker and less refractive (!?)

3) the actual material effect that here looks not glass but plexiglass, that I'm not able to replicate.

Could you drive me on the right path, with suggestions on how to set parameters, shaders, and whatnot? (also readings)

Thanks,

Tom

Welcome to the Houdini clan.

I might be able to help with Q 1 and 2

1. Use PolyExtrude and tick on Output back…this will give you thickness with the inner polygons.

2. If you are using the Mantra Shader, have a look at Attenuation under Refraction. Play with the Density slider to give coloration based on thickness/density.

Let me know if this was helpful in any way.

Hi thanks for your hints.
I've followed your first suggestion without problems. I've extruded outwards (distance=0.02). I've then reversed to make normals of the outer surface pointing inwards, and then applied a Material.

The render that I attach has this configuration:

SURFACE
1) No diffuse
2) Reflect base (Intensity = 0.7)
3) No Reflect coat
4) Refract (intensity = 0.8, Attenuation enabled, color black, Density = 0.5)
5) No subsurf, no emission
6) Opacity (scale = 1, Enable opacity falloff (par = 0, perp = 0.7, rolloff = 0.8), Enable faux caustics (Tint = 0, Shadow = 0.5).

SETTINGS
Inside IOR = 1
Outside IOR = 1.488
Fresnel blending enabled

It does not either seem the material above. The border of the plastic, which I would like to be darker, here are brighter instead. Boh?!

But, as you can see, neither I do not know where and how to improve the settings, nor what to do to replicate the material that I've made in Blender.

Tom

Werner Ziemerink
Welcome to the Houdini clan.

I might be able to help with Q 1 and 2

1. Use PolyExtrude and tick on Output back…this will give you thickness with the inner polygons.

2. If you are using the Mantra Shader, have a look at Attenuation under Refraction. Play with the Density slider to give coloration based on thickness/density.

Let me know if this was helpful in any way.

I can't view the tiff file you posted. Maybe convert to png and post again.

Does clear plastic not have less IOR like 1.4? Not that it would change it drastically, but I remember something like that.

Hi yes, sorry.
In the meantime, I've generated this image.

1) No diffuse
2) Reflect base (intensity = 0.7, specular min = 0.1)
3) No reflect coat
4) Refract (Intensity = 1, min = 0.1)
IOR inside = 1.488 (plaxiglass?)
IOR outside = 1

Then, I'm not using Attenuation because It made everything, and not only the border, darker.

Have you some other suggestions on how to improve it?

Thanks in advance

Werner Ziemerink
I can't view the tiff file you posted. Maybe convert to png and post again.

Does clear plastic not have less IOR like 1.4? Not that it would change it drastically, but I remember something like that.

try this:

1.create a surface shader builder, go inside
2. add a surface model, if you are in h15 this will add a compute lighting and connect the proper outputs
3. turn off the diffuse model
4. set the refract model to GGX
5. set refraction roughness to 0.001
6. on the opacity tab, turn on Enable Fake Caustics
7. set the Fake caustic Shadow value to 0.5
8. set your Inside IOR to 1.488
9. apply this to your plexiglass box
10. render with PBR

This works for me in H15 without the need for attenuation

Hi thank you very much.
I've followed your suggestion and obtained this.
I am quite satified, even if it looks like more glass than plexiglass.

Thank you