I'm looking for a efficient way to do image masking within Blender (using the masking tool) à la After Effects. Basically, I want to cut out my images from within Blender instead of doing it destructively in an image editor.

Typically, in AE, I would precomp an image then do the masking in that precomp. I'd like to mimic this workflow in Blender; however, it always seems overly complicated.

I have considered creating a separate scene with the same dimensions as the image and masking there, then bringing it into a master scene to assemble in 3D space, but I'm not sure I can map this to a plane.

Sorry that I may not be explaining this very well. If anyone is familiar with AE, then you'll be familiar with what I'm trying to achieve.

  • $\begingroup$ there is many different types of maskings ,if you have any link to AE example it will be fine $\endgroup$
    – Utas
    Commented Jun 26, 2013 at 13:25

4 Answers 4

  1. go to node editor and enable use nodes
  2. add mask node and mix node
  3. in uv editor change from paint to mask (if you want a mask image, upload that image to uv editor, the mask will be placed over your image) basic set up
  4. LMB+Ctrl to add point on the curve, close curve by enabling toggle cyclic
  5. use this mask as input for mask node and plug mask node to factor of the mix node

for rotoscoping you could use this add on, see this for more info.


To be honest, there is no single universal "best" masking or keying way exists for all images. However, there would certainly be the "most suitable" way for specific images regarding specific needs.

Currently, there are two main way for masking within Blender, one is regular masking. which can be created in UV/Image editor or Movie Clip editor; Or you can use matte compositing in Node editor, which is mainly keying methods. Both ways got their own advantages and limits. So, sometimes you need both to work together. Regular Masking is easy, but Color Keying is a bit complicated and needs experience a bit. But I believe you can master them well if reading wiki and watching some neat tuts on various sites, such as Youtube and CG Cookie, etc.

For regular masking, HERE may help you some:

Masking editor (Image from Mango project)

For node keying, HERE may help you some:

enter image description here

  • $\begingroup$ This was flagged as offensive, could you perhaps use a different image in the node keying example. $\endgroup$
    – iKlsR
    Commented Feb 8, 2014 at 2:51
  • $\begingroup$ Hmm, maybe, I'll try now. Thanks for reminding. $\endgroup$ Commented Feb 8, 2014 at 3:16

The closest thing to a precomp in blender's compositor is a node group. selected nodes that you wish to precompose then pres Ctrl G. Hit Tab to enter/exit the group.

NOTE: Not all input and output nodes can be grouped.

See here for more on masking.

Basic Node setup


For this you can practice with different types of keys in add>matte. for masking mostly difference key,color key and distance keys are used. Try something like this: add an image to blender compositor

enter image description here

add any one of the key and pick the colour you want to remove.Experiment with different types of keys and do fancy things like combining two images enter image description here

  • $\begingroup$ Please try to answer the question. Your not telling how to mask out and create a "precomp". Your telling how to use keying matte. $\endgroup$
    – CharlesL
    Commented Jun 23, 2013 at 18:36

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