Matte Objects not working as expected

[voltaire585]

We are finding a few problems with the matte material option in 1.5 and 2.0

1. matte objects seems to receive self shadows and some shading that appear in diffuse and alpha. Really the only shadows on a matte object should be from non matte objects.

2. ideally a matte object with materials, should appear in reflections on non matte object surfaces.

Unless Im missing something

[gordonrobb]

The Matte object is more a Shadow Catcher object.

[gordonrobb]

The Matte object is more a Shadow Catcher object.

[darkline]

They changed how it worked.

http://render.otoy.com/forum/viewtopic.php?p=177710


Personally I prefer the old method, as it seems the new method does not take into account the light bounce from the matte object onto anything else in your scene. If you've got a white sphere sitting on a matte object green table, then it looks unrealstic as there is no colour bounce taken by the white sphere. It seems the new method, if I understand it correctly is a post 'cheat' to fake reflections only, not light transmission.

I'd like it if they gave you the option of using the old method too.

[JuM]

They changed how it worked.

http://render.otoy.com/forum/viewtopic.php?p=177710


Personally I prefer the old method, as it seems the new method does not take into account the light bounce from the matte object onto anything else in your scene. If you've got a white sphere sitting on a matte object green table, then it looks unrealstic as there is no colour bounce taken by the white sphere. It seems the new method, if I understand it correctly is a post 'cheat' to fake reflections only, not light transmission.

I'd like it if they gave you the option of using the old method too.

I have multiple licences and upgraded them to 2.0. I knew they didnt implement the different render targets yet. However i could not imagine they were not able to make working matte system for compositing.
So its not possible to use Octane in serious projects while missing render targets and matte shadow with light bounces!!! this is ridiculous.

[voltaire585]

A shadow catcher is all well and good, but what is the point of the shadowcatcher catching its own shadow. It makes the matte almost useless in a compositing pipeline as it leaves shadow and lighting artefacts in the render and alpha.

The matte should cast shadows (and reflection + GI) onto the non mattes, but be transparent in alpha, (except where the matte catches shadow for a non matte).

Maybe once the render passes are available in the Max plugin, this can be remedied.

[darkline]

It used to work as you describe, I think more voices need to speak if they are to change it back.

For me there is another problem with matte objects and that's picking up tons of shadows from GI. It makes compositing horrible. Everytime I do a composite I can see shadows all over my matte object (say a floor) in the alpha channel. This happens even if there is only one daylight in place and a single harsh shadow. It makes compositing almost impossible. I suspect this is from multiple light bounces, environment shadows etc... There needs to be some shdaow density controls on the matte object or something similar so we can tweak the intensity of the shadows recieved or choose to exclude environment from casting shadows onto it.