SkIndigo 3.4.12

[CTZn]

Back with another smart remark!

I usually did diffuse transmitters by setting a colour in Sketchup, giving it a certain amount of transparency (low) and reverting the shader back to diffuse if it was automatically converted into specular.

..lately I was considering that this procedure caused very dark diffuse transmitters, and only a few minutes ago I took some time to check the exported material hierarchy. SkIndigo at the moment converts my "simple" diffuse transmitter into a BLEND material, which mixes two sub materials (exactly as I knew it). The two sub materials are a DIFFUSE MATERIAL and a DIFFUSE TRANSMITTER MATERIAL, and that I can't understand. In the Indigo GUI, I manually converted the blend material into a straight DIFFUSE TRANSMITTER MATERIAL and that did the trick.
..only thing: I cannot change the diffuse transmitter material's opacity from the indigo GUI, or at least I wasn't able to find the property...

Is this a material conversion bug or something?

Thanks Dale!

Hi Pibuz I'm not Dale

Take a diffuse material, add a little transparency and there will still be a diffuse component scattering light back: that's the benefit of blending a diffuse with a diffuse transmitter. In this regard the material conversion from SkIndigo sounds correct.

The diffuse_transmitter material itself does not have a transparency parameter. There is only its albedo to multiply the transmitted light with: white and the colour are unaltered, just scattered rays and black: no light passes through, as if it was fully absorbed.

Knowing that the blend material should make sense, granted that you started with a simple diffuse material wich does only scatter light back.

edit: I'll be more specific: the diffuse transmitter alone is an ideal transmitter: it does not correspond to a real material because light is never bouncing on it (always passing through). It was meant from its conception to be blended with other materials.

It is reasonable to imagine that exporters can use the diffuse transmitter by blending it without exposing it directly to the user.

[CTZn]

Practical example:

I want a diffuse to transmit 25% of its light through.

I will need a blend of that diffuse (material A, blend: 0.75) for light backscattering with a diffuse_transmitter (material B), in general of the same albedo.

The diffuse transmitter will be fully transmitting but 3 times on 4 it will be the diffuse material sampled instead. That's more or less how it works.

It's a bit long-ish but I'm develloping the explanation to offer several ways to get the idea. Hopefully

[Pibuz]

Ok got it.

I didn't know that I could approximate the behaviour with "numer of times" the light passes; I was thinking more to a "sum" of effects: so I basically intended the second blend material as a null, the first one being a simple diffuse.

[CTZn]

Fine. Wait no, weird material but if that's what you need, fine. Note that the light passing through the null material will not be colored.

Blend with null materials without a map to control the blend parameter are of the noisiest I think.

edit: it used to be, Indigo might handle the case better now though. Recall the Ghost glass wich is a blend of a phong with a null material. This blend might be the noisiest in fact.

[Pibuz]

Indeed.

The effect I want to achieve is not only controlled by the opacity of the SketchUp material (the blend factor, in short terms), but mostly by its base color hue: too dark colours will result in no pass-through materials..
A dark coloured green tone won't allow any light to pass it even at the SU opacity of 1, which is the minimum value, translated with a 0.01 BLEND factor inside Indigo.

[CTZn]

Well the light will always pass through; think of the diffuse_transmitter albedo as a multiplier. A black transmitter is therefore a special case.

But then yes you might need to compose the blend in Indigo to use a (much) lighter albedo in the transmitter.

[Whaat]

Indeed.

The effect I want to achieve is not only controlled by the opacity of the SketchUp material (the blend factor, in short terms), but mostly by its base color hue: too dark colours will result in no pass-through materials..
A dark coloured green tone won't allow any light to pass it even at the SU opacity of 1, which is the minimum value, translated with a 0.01 BLEND factor inside Indigo.

Hi Pibuz,

To get more light through, try increasing the 'B' texture parameter. Yes, this will affect both the Diffuse and DT components of the Blend material so if you want more control, you will have to edit it with the Indigo GUI. For example, you might want to increase the 'B' parameter for the DT material alone.

Hope this helps!

As an aside, I do plan to properly expose Diffuse Transmitters in SkIndigo to make things more consistent with the Indigo GUI, just haven't got to it yet.

[Pibuz]

Hey Dale another input from me: I'm using more and more exr env maps in my latest scenes, and since there frequently are emitters too I often find myself pushing surreal values. Would it be possible to make the "emission scale" field more wide? and additionally, would it be possible to make the numbers being automatically separated by points (so that 1000000 appears as 1.000.000)?

[PAO]

I just installed this version of SkIndigo, and I tried to add another environment maps on the skindigo settings interface, now I want to delete the old enviroment map from Sketchup material panel but I can't do it with the standard "right-click and delete" steps. No Sketchup error messages appear.

Is there a way to manually remove the "Environment map" sketchup material?

Thank in advance

[cotty]

I just installed this version of SkIndigo, and I tried to add another environment maps on the skindigo settings interface, now I want to delete the old enviroment map from Sketchup material panel but I can't do it with the standard "right-click and delete" steps. No Sketchup error messages appear.

Is there a way to manually remove the "Environment map" sketchup material?

Thank in advance

Does this help in your case?

[Pibuz]

Hi Dale, hi all. Back to report a very strange behaviour.

I usually prepare my own environment materials in sketchup manually: I mean I reproduce all the basic steps, creating a new SU mat, recalling the SkIndigo mat editor, setting an emission texture, moving the material on a non-off layer and so on..
I recently learnt the automatic procedure explained in the youtube tutorial, and it works. But when the render is launched and I go in the "scene" panel of the Indigo GUI the texture path doesn't appear in the "background settings", "texture" field (like it happens with the "manual" configuration) which is blank instead. Trying to use the rotate function specifying an angle makes Indigo halt and freeze.