Mask/Roto Texture of Image Plane

How can I mask or roto things off an image texture in Blender 2.9x ?

I figured out that I can use Texture Paint with Erase Alpha Brush:

But I’d like to mask off things and still be able to animate the mask, similar to roto mask in Natron:

It must be somehow possible to do this in Blender, anyone any idea?

An idea:

I think the solution would be to mask the image in the image editor and then pipe this image into the shader…

but since over a hour I try to figure out how to draw a mask in image editor / compositor…
(edit: control + click in the image editor to draw a mask)

This tut helped concerning the masking: https://www.youtube.com/watch?v=fziA1Vw4L98

But still not able to mask things visible off… anyone?

Here again the question:

How can I achieve this in Blender:

???

You can animate the from min value of the map range node

Thanks for this, nice trick… learned a few things…

But mixing shaders make them only half visible:

.blend file attached: shader_wise.blend (989.3 KB)

here user vklidu presented a solution with boolean modifieres, which is also neat…

But I still like to have some kind of roto in texture mode, similar to Natron’s roto node, just to be able to do 2d comped animations fully in Blender… or am I naive?

Take the Alpha from the Lower Texture slot and run it up to the Factor on your mix shader…

Wow, that was quick… great, this works!!

Just to keep on going with this solution, could I rotate the map range?

some slider which is mixing X + Y … ?

Now its starting to get really cool, figured out the rotation too…


thinking about ripples instead of a linear line :slight_smile:

shader_wise_roto.blend (944.2 KB)

One Idea…

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If you want the animation to be always on a specific axis, you can use the position vector from the geometry node. Need to change some math though.

If you have some time, please tell as more bout this… still a bit lost in all the nodes …

Can you try this, the plane is on the xy plane:

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@lehuan5062

YOU ARE MY HERO!

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