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I added an object - plane, rectangle. Went to edit mode and deleted 3 edges, left only one. Exit edit mode and added screw modifier to this edge. This way I can animate drawing of circle with changing angle of screw modifier.

enter image description here

Since I need that this animation be rectangle and not circle, I added cube, hidden and not rendered. This cube is object for Boolean Intersect modifier for Edge.

enter image description here

With some Shift+D, little materials here and there, etc. final product is this:

enter image description here

Is there any chance that I can add text on grey rectangle which would also radial sweep appear? I'm googling all day and cannot find a way (newbie :) ).

One important thing - project is in Eevee, not in Cycles.

Thanks in advance.

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  • $\begingroup$ As for now, I'm using workaround where I rendering solid rectangle .png image with desired text (no matter in Blender or GIMP) then using that .png as Image Texture for radial sweep edge. But I really would like to learn how to accomplish such a that with text, directly in 3D Viewport. $\endgroup$ – stiw47 Sep 20 '20 at 7:02
  • $\begingroup$ I that a text object or a text on a texture? $\endgroup$ – lemon Sep 20 '20 at 7:22
  • $\begingroup$ As said, now I'm using workaround with text on texture - png image with text on it. But question was how this kind of radial sweep can be done with text object in 3D Viewport, i.e. is it possible to make that text object appear radial in same way as grey rectangle on gif in my post above? $\endgroup$ – stiw47 Sep 20 '20 at 8:17
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Using shaders (Eevee here but works for Cycles too).

enter image description here

enter image description here

Top part:

Presuming Z is facing the camera, we take X and Y as base for the calculation.

Artan2 gives the angle between -pi and pi for each X and Y position.

Bottom part:

Now from 2 values the current frame and the amount of frames, translate that in order to have a value between 0 and pi.

Then translate it between 0 and -pi (for the left part) and between pi and 0 for the right part.

Transparency:

We compare that to the effective X Y angle and if OK (one or other into the good interval), set alpha to 1 (no transparency).

Another way, that can be considered less maths and/or more flexible is to use a gradient texture with radial mode:

enter image description here

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    $\begingroup$ Thanks a lot my friend. Will not be able to try this before evening (in next ~8 hours). Will follow up. $\endgroup$ – stiw47 Sep 20 '20 at 9:23
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    $\begingroup$ Thanks a lot once again. I downloaded your .blend's and they are exactly what you said - they are working. I still have no enough time to import it in my project and to see will they work out of box, but thing is here very clear and I am pretty sure it must work with or without little tweaking (IDK, for whatever reason maybe will be some issue triggered with my project settings). Answer is fully accepted, cause this is exactly what I looked for. $\endgroup$ – stiw47 Sep 20 '20 at 11:12

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