Textures with alpha channel - How build them?

Hello, developers. I need help to understand how to create and apply alpha channels textures to create effects of glare, reflections, transparency and roughness.

The 3D assets I have been already made for X-Plane had basically two RGB textures: the albedo / diffuse ('object_name'.png) as a daytime texture and the emissive (' object_name'_LIT.png) as a night texture. I now intend to go to the next step of knowledge, which is to add details of transparency and PBR to my models. The few what I know so far is that I will need to create RGBA textures, that is, textures including an alpha channel to create the desired effects.

Suppose I want to model a house with exposed bricks on the external walls, windows with transparent glasses and an aluminum roof. I want to apply the following effects to the model: (1) Bump Mapping on the bricks, transparent window glasses with reflections and have brightness and at last reflections and shinning on the aluminum roof.

The first question is "will I need to create, for example, three different 3D objects, as one for the walls of the house, another for the roof and another with the windows"?

The second question: "will I need to create three textures files, one for each 3D object, that is, each texture file with an alpha channel for the desired effect?




The last question: "Is it possible to model the whole house in a single 3D object and create and apply a single texture with alpha channels, being a channel for each expected effect"?

I appreciate any help.

Thank you.
 

tgibson

Resource contributor
I would think that the answer to some of those questions will depend on the tool you are using to build the object, what you are using to paint the textures, and the final format of the texture files?
 

Vitus

Resource contributor
1. All objects that share a texture (and aren't animated) can be merged into one object
2. You're essentially looking at only two types of materials here. An opaque material for the bricks and roof and a transparent one for the windows. So you'll need two materials.

But as Tom pointed out, the details depend a bit on what you're working with. Do you have access and the right to the 3d model? Because, if you pack roof and walls into one texture, you must adjust the uv map of the 3d object accordingly.
 
I will try to summarize my doubt. I am modelling for X-Plane using Blender 2.8. The model I built for tests has two objects called bricks and glass. Both are using the same texture file bricks_glass.png. I want to apply a bump mapping on the bricks and becomes the window's glass transparent. Can I do all of this stuffs with just one Normal texture? Or will I need to create the wall (with bricks) and the glass as two individuals 3d models and use two separated Normal Maps, each one with the desired effect on it, that is, one having bump mapping (for the wall) and the other with transparency for the window's glass?
 

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Pyscen

Resource contributor
Yes, you can have the glass and bricks in 1 Normal/ bump map. How do you want the glass to appear, closer or farther compared to the bricks? If farther, a shade of black the glass to be or closer to black.
 
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