[oz42]

Hi, I'm trying to make a speaker grille (mesh) using a 2 layer bsdf and I just can't get it to work. I've read around the subject in the tutorials forum and elsewhere but no one seems to have my exact setup.

Here's the problem;

I'm trying to re-create a speaker grille like this;



and this is the clipmap pattern I'm using (I use it inverted);



the material that I need for the mesh is this (a 2 layer material to create the right shine);



but when I add the clipmap image (it's just a pure black and white tiff) to the tramittance slot on both BSDF layers I get this;



where as, what I want, is this (simulated with a 1 layer material - no shine);



I'm assuming the 2 layer material has problems because the 'Reflectance' layer has a Nd greater than 1 and therefore it is causing the light to refract as it passes through?

Does anyone have a solution (or another method) to create a mesh with a shiny grey solid area and completely 'blank' hole?

Thanks...

[Mattia Sullini]

The problem you are getting is given by the fact that you are using both for the transparent part and the opaque a material with an Nd different than 1
(in the second pic from mxed you have 2.5). What you shoul do then i this:

1-transform your clipmap so that you get two weightmaps whose brightest grey is the same of the weight of each opaque BSDF (in your case 30% grey and 70% grey) and use them to weight each BSDF

2-set each BSDF for the opaque part normally

3-use then your original clipmap (black and white) and invert it to weight a third BSDF that will stand for the holes. This BSDF's settings will be ref0:0 ref90:0 transmittance:100, Nd 1

If i have understood correctly, you should then be done

[DrMerman]

EDIT: Beaten to it!

Hey oz42,

Check out my decals tutorial, linked below

The solution is to use 3 layers with weightmaps: your main 'White Diffuse' layer; your 'Reflectance' layer; and a third 'transparent' layer. The problem with this is that when you add a weightmap to a layer, that layer's weight value becomes irrelevant (see the 'For 2-layered materials and beyond' section in my previous tutorial.)

Sorry this isn't more comprehensive but I'm stuck in the middle of something right now. I'm going to be covering this in one of my video tutorials though

Here be the tutorial :

http://www.maxwellrender.com/forum/view ... hp?t=18048

Here be the extra maps :




And here be the MXM for you to deconstruct :

http://www.drmerman.com/mattFTP/Weightm ... ersion.mxm

Cheers,
Dr Merman

[tokiop]

hi Oz!

not sure but it might be because the shiny layer doesn't have ND = 1 ..

You can also try the method with (ghost layer) / (color + reflection layers) with inverted clipmaps/weightmaps..

[edit] whow, the forum is responsive !

[oz42]

wow, thanks guys, v quick reply. I'm always impressed by how much help there is here - I'll try to return the favour when I get better.

Thanks Mattia for the great explaination I didn't realise I needed a third layer but this makes sense now.

Thanks DrMerman for the extra images, I'll use these.

tokiop - yes I'm very impressed with the reposne as well.

I'll post the finished material when done.

Cheers,

[oz42]

thanks guys - done.



it's slightly different from DrMerman's mxm but it seems to work - I've followed Mattia's instructions for the third 'holes' layer

[Mattia Sullini]

[tom]

The solution is only 2 BSDF and 1 B/W map.

UPDATED

[DrMerman]

Touché

[Mattia Sullini]

Much better Tom's way. That is a reason why TOM is TOM and me is me, indeed!

[martgreg]

[oz42]

nice!

but it doesn't seem to give the result I was looking for;

the 'holes' seem to have retained some reflection and the solid area doesn't have the shine I was looking for.

[Mattia Sullini]

First one has to be lambertian, otherwise you will see those highlights on holes

[tom]

Mattia is right, first one has to be lambertian.

[oz42]

1st BSDF is lambertian with a Nd of 1. Not sure why it isn't working but Mattia's previous method worked fine so I'm udising that one.