I amtrying to understand the specular, reflection, and Hard mapping.
Lets say I make a sphere or ball in Blender. I now make a texture for it in Gimp. I want the ball to appear to be made of a shiny specular Iron with a dull white paper label stuck on it. In Gimp I make a grey image (Iron) background and then I place a white rectangle (dull label) in the center. This is my color map.
I now make a bump map so that the sticker appears to be raised. No problem! but after making a specular map, hard map and even reflection map, I can not get the sticker to look dull enough and have the ball be a shiny Iron. It seems that I should be able to make a spec and Hard map with a solid black rectangle to replace the white one to get rid of all specular highlight in the white sticker. There are only subtle differences.
Is it not possible to accomplish this in this way?
EXPERIMENT
I now remove all maps except the color map. I load the color map into gimp and change the white label to solid Black and lighten the grey background a little. I now save this as a reflection map and load it and asign it to the ReF only. I now have a color map and this reflection map.
I turn the reflection slider down to 0.
Why does this not stop the white label from showing up in the render?
I want to be able to accomplish the above without creating a seperate mesh for the sticker label.
The color map is wrapped around the sphere as a hole. I know that I can create different materials for different faces. I can accomplish the task in other ways I know.
I am trying to understand how the mapping works. Is it not possible to do it the way I described above using one material with the different maps? Is’nt this what specular maps etc. are for, to allow you to use one material?
Also in the experiment that I did that is listed above concerning the reflection map. Is this way it should work?
Thing is, all the shader values are mapped to all of the faces of the material (when you say that the color map is wrapped around the sphere as a whole, that’s only because the material is wrapped around the sphere as a whole).
You could map the label to an empty, but then that empty would have to be parented to the object (and its material) because you can’t add a material to an empty. The way to map your reflection (or spec or whatever) is thru the stencil option, but, even then, the map values are for all of the material and not the texture.
If there is a way I’d like to know, but the above is as I understand it, and I like it because seperate materials give much flexability with the new render options.
It is true that all of the shader values are mapped to all of the faces of the material but here is what happens as I understand and from putting it into practice.
Take any object that you want to texture using only one material. Lets say a shiny ball with no label on it. You want to show that the ball is not consistently shiny all over. You don’t want to use procedural textures because you want to have more control over where the ball is shiny. If you make a specular map in a paint program by starting out with a close to black grey background and add very light grey spots. In Blender create a sphere and give it a light bluegreen material. Now load the specular map you just made as a texture mapping it to Spec only. Now you must go to the specular slider in the shader and turn it down to 0. If you render you will see that your specular map now controls the specularity of the object.
You do not need to use the shader specular slider any more.
Unserstood. But the whole texture is mapped to the whole material index and shows the spec in the chosen area based on the color values of the spec map. (so if you want a label on a bottle you would need to map a texture (grid) to figure out where on the UV’s of the bottle the label part of the texture will be displayed, draw up a new texture and remap it [and even then I’m not sure it will hold up if the lighting is changed]).
Even then the label will inherit the material settings of the metal settings of the shaders. In your last example if you turn down the spec because you use a texture for spec values then the color values (and maybe the var slider) are the only control you have over the specularity of the metal material. You still won’t be able to make the paper look like paper while keeping the metal (or glass) correct.
I’m only answering because the big guns are not. I’m no boffin at this sort of thing. And my answers are based on the fact that I find seperate materials the best way to do this, though I have used seperate objects.
All of this conversation is helpful and I hope it will help others that read it.
Greybeard a special thanks for the demonstration. If you have time see if you can create a shiny sphere with a dull label (label of any size) on it by just using texture maps.
My ultimate goal is to be able to create low poly objects with great detail through the use of textures and UV mapping without using the material colors in blender.
Example: would be to create a low poly dune buggy with dried mud splashes, scratches, decals etc. The buggys body would need to show high glossy areas of say red and dull areas of red because of weather damage as well as ware and tear.
I have a tutorial showing how this dune buggy example is done in this way, but it is not 3D application dependent. I have been testing this in blender but the results have beeen real subtle differences.
Greybeard, thanks for posting those pics (I don’t have webspace so I can’t).
Midije:
I want the ball to appear to be made of a shiny specular Iron with a dull white paper label stuck on it.
And those pics illustrate that you can map the label but, without a seperate material, the material values are the same for the whole sphere.
Now that I know how you want to use it my solution would be to render a model (possibly high poly) with UV and Texture maps with seperate materials and MapTo chanells to get reflec and spec maps. Render from all sides and use those images as UV textures for the low poly model.
The effect is just reversed. A shiny label with a dull ball but the concept is the same. Now I have to go back and see what I did wrong. You were right, I am doing it right in my head but some where I messed up in my practice or I am having a problem with my blender application. Thanks a lot for helping out.
It just did not make sense that it could not be done.
Hey, I figured out what I was doing wrong. “My reflection map”, and I was also using a white label which was the same color as my specular color. This fooled me somewhat. For my test I fixed it by changing the color of my specularity to red instead of changing my color map and adjusted my reflection map.
I also found out that I could create the effect without the reflection map all together. In order to do it I had to turn the reflection slider all the way up. I am sure this would cause a problem when the lighting changed though.
Without the refelction map, and the reflection slider lowerd the specularity would bleed over into the label.
