Specular colour and metalness map problem

rahulcamma

I am trying to understand PBR workflow.But i am not able to understand certain things.


1)The specular colour looks yellow even when the specular map is blue.There is no albedo map in this example.

The problem occur on the area where there is coloured reflection in your specular map and at the exact same spot you have a different colour in your albedo map.

.


2)In metalness map the black area is suppose to be non reflective but i am still getting reflection on the black part of the texture map.



I tried to find the solution before posting here.But i wasn't able to find it.

Obscura

I can't really say anything about the first question, but....
"2)In metalness map the black area is suppose to be non reflective but i am still getting reflection on the black part of the texture map." --- This is not true. Everything is reflective in the real life, they can just look not reflective because of the roughness.
As far as I know, metals has reflection value between 90-100% and the non metal materials has reflection around value around 0,04. If you have a a reflection value on 0,04 , and the roughness value on 1, then it will look like it isn't reflective. But it is, its just really blurred.

-There are many articles about PBR over the internet. The ones on the Marmoset's site are really good. There is an explanation about fullcolor reflection maps too.

http://www.marmoset.co/toolbag/learn/pbr-theory
http://www.marmoset.co/toolbag/learn/pbr-practice

Khaja

A metalness map won't mess with your reflections as it's just there to say whether or not a surface is made of metal or not, and therefore whether or not the specular will be tinted with the material colour or not. You should be looking at roughness maps to adjust your relective values.

*EDIT* actually ignore that i was confused by the fact that a metalness map was in the relectivity slot

almighty_gir

on question 1:

this is down to energy conservation. because your reflective colour is purely blue, it removes any blue from the diffuse (which is white) which leaves green/red still being diffused, green + red = yellow. so you're seeing a yellow diffuse with blue reflection in the first image.

in the second image, anything that's black in the metalness channel will still have a reflective value of 0.04.

rahulcamma

@Obscura Thanks for the reply.So the way i have understood is the key element when using metalness workflow is roughness.

Metalness maps just decide which part is metallic or non metallic.But real effect is being conveyed through roughness map.

Again thank you for replying

rahulcamma

almighty_gir wrote: »

on question 1:

this is down to energy conservation. because your reflective colour is purely blue, it removes any blue from the diffuse (which is white) which leaves green/red still being diffused, green + red = yellow. so you're seeing a yellow diffuse with blue reflection in the first image.

in the second image, anything that's black in the metalness channel will still have a reflective value of 0.04.

Thanks Lee that clear up the confusion.:thumbup:

Obscura

Metalness map-->black = 0,04 reflectivity, white= 100% reflectivity. black=non metals, white=metals
So it has "real effect", but yeah you need to take a roughness map into account if you want to make your non metal surfaces to look like they are "not reflective".

rahulcamma

I thought that metalness map are like on or off.White being 100% reflective(metal) and black mean 0 % reflective(non-metal).

But now its clear. Thank you for your time.