[piroshki]

So I've jumped into Maxwell again after a few years, and upgraded to V5, so I could do a quick interior render.

I am using materials I have used in the past, and see that I am getting very strange behavior indeed: some materials with 0,0,0 transmittance are now translucent, which is obviously a big problem. I don't think I am doing anything strange...

Has anyone seen this as well? Is there a fix?

Tom

[luis.hijarrubia]

We would need a little more info. Wich engine are you rendering with? What else have that material? There is no Known issue about non desired traslucent materials.

[piroshki]

Hi Luis -

Using 5.1.1.33 release x64

Materials are just a blend of two BSDFs although I just noticed that the layer blending was marked as "Additive" instead of "Normal". I am going to re-render and see if that makes a difference.

Tom

[piroshki]

No difference. I still get materials with all layers at 0,0,0 translucency are appearing translucent.

Happy to send a scene - just let me know where to send it

T.

[luis.hijarrubia]

I don't know how they usually do. Let's ask forum moderator.

edit: He says the easiest way is to send a link in a support case (through portal)

[Forum Moderator]

Hello Piroshki,

That's quite weird indeed.

Thank you for sending all the information.

The answer is in the materials; both the wood and the ceiling material have similar problems. This is how the layers are formed:

mat opacity1.png

Basically, it has two layers with an opacity lower than 100, so the base layer is not opaque and nor is the top one.
In one material, both layers are in normal blending mode and in the other one, both are in additive mode.
You could solve this by raising the bottom layer opacity to 100 and setting it to normal blending mode. By doing this, you are creating an opaque base and then adding the top layer.
Most probably you got confused with the procedure where you create a layer (100% opaque) and inside you add two BSDF with different weights. The difference is that in one case you are playing with the weights of the BSDFs and in the other with layer opacities.
When you play with the weight of the BSDFs, you don't get transparency, but just the mix proportion with the rest of the BSDFs inside the same layer. So you could have only one BSDF in a particular layer and it would be the same setting it to 100 or 1, as Maxwell normalizes the mix of BSDFs so they always add up 100. If you had two BSDFs, it would be the same setting them to a weight of 60 and 40 than 6 and 4, for example. But in the case of the layer opacity, this is not the same at all.

All the best,
Fernando

[piroshki]

Hi Fernando - thanks, this is helpful. It is the first time I ever noticed this effect, even though I have been using these materials for a long time. Your explanation makes perfect sense - as usual the problem is usually found between the chair and the keyboard

[Forum Moderator]

Well, the problems can be in the chair, the monitor, the user, the software,... We can all make mistakes. That's why it's always important to check the cause of the problem. Thanks for sharing it with us. This can also be a way of learning for others.

Cheers!
Fernando