How would I model this?

Support Modeling
1

Hello,

I am a greenhorn with about a week of practice in Blender. I spent full time on interface tutorials and such.

If you have a moment, you might be able to push me into the correct directions for my current task:

I was looking into how to juice up some video with blender scene overlays, mainly the kind of post editing as in news shows and documentaries, as I am helping friends with setting up a youtube channel. I am trying to model a logo that I have as transparent PNG as a 2D mesh. I have attached it here:

Two semi-opaque rings which are gradually becoming transparent towards inside, but blank/cut on the inner circle. I have found settings to make material more or less transparent, but I guess I need a node function that controls transparency based on radius. I haven’t learned enough about this yet, do you have a suggestion?

Cheers,
Kai

2

Gradient texture as alpha map. Greyscale values on the texture controlling the material alpha property.

3

Tried a Texture Coordinate node Object output as input to the Gradient Texture node set to quadratic sphere. With a bit of fine tuning I got a the circle transparent in the center. But: when moving the center, the texture seems locked to the scene, not to the circle. The object property of Texture Coordinate seems to have a different meaning than what I thought. How do I lock the texture with the circle?

4

So Cycles then. That setup works just fine

upload.png1920×1004 270 KB

5

That helped heaps. Many thanks!
How did you solve the cutouts? I might have created my rings with too few segments and added a Sub modifier to it - now I cant get clean cuts.

6

Several ways. One is to add a new object above, and use a material with only a holdout shader for that.

Subdivision surfaces need to be controlled with the structure. https://vimeo.com/2450612