Blender: Creating Complex Geometry the Easy Way

[ODdOnLifeItself]

Depending on what it is that you're trying to do, modeling the objects can be fun or can be a royal pain. In the following example, the main sphere could have been modeled, but you can probably tell from the look of it that it would have been difficult and time consuming to do.

Alpha texturing to the rescue. Since a texture (image) can control many things, besides just color, there are a lot of things that can be done!

In the following, the simple shape that you see all over the main sphere was a simple (30 sec) drawing made in Xara, with its excellent (and easy) shape tools. The inner, star shape was a cut-out. (ie. the inner part of the circle is see through)

By going into Blender and mapping the texture to ONLY the Alpha channel, the original color of the sphere remains the same, but where there is transparency in the original image, there is a hole in the mapped-to object. (In the Materials tab, the Alpha slider under Transparency needs to be set to ZERO. (to make the object transparent) Then, the applied Texture is saying "make it transparent, but only where there is transparency in the mapped image".)

By making the texture repeat (16 times in X, 8 times in Y) on the sphere, a complex geometry sphere is created only taking a few, scant moments.



Blender does a fine job on mapping the texture, creating the complex geometry. Below is a close-up of the mirrored sphere on the right and you can see by the reflection of the larger (mapped) sphere that it has essentially created the desired object, though the geometry has remained a simple sphere, only with a mapped texture. For many objects, this is a simpler way to (seemingly) modify the geometry.



For example, if you had a large table scene and on that table was an ornate Kleenex box, which you needed a curvy S-shape on top, you could model the S-shape; though you would have to integrate that into the already created "cube" shape of the box. Another alternative (using the method described above) would be to have a simple image that has the curvy S-shape transparent with the rest of the image solid. Now, just by adding that to a texture channel (and doing the alpha settings as mentioned above), you will have the Kleenex box with appropriate design and without spending any (additional) time modeling to get it.

Take care

James

[wizard509]

Very cool James.

[angelize]

Oh that makes me want to play! My imagination is shifting into gear. But It's Monday morning and I only have a few mins "forum time" then I have work to do! But I will try this later.

[ODdOnLifeItself]

Thanks, Larry and Frances

I'm glad you liked it.

You can really get a lot of mileage out of the technique.

If you were making a cute little scene of a jungle and wanted a few trees in the background, there's nothing wrong with importing them (with alpha) and placing them in the scene...placing 2D images in the 3D world. In other words, the background might take 2 hours to model, but only 30 mins to draw, so depending on effect, either option might be appropriate.

Take care

James

[guyke]

Thanks James for the info and demo. Right now I'm working on the yellow-submarine-tutorial, but after that I certainly will try out the alpha textures.

[guyke]

Small variation on James' theme ...



I'm sure Gary will recognise his yin-yang tutorial.

[ODdOnLifeItself]

Hey, that looks cool and trippy.

Nice work, Guy!

James