I have an image of a human brain, but I only need the contour of it; its outer shape and not everything that's on the inside of the brain. I tried using Trace Bitmap, but I still got the inside of the brain. Hope my question is clear and thanks in advance for any help.

  • Welcome to GD.SE - Please look through tour to get a sense of our community – who we are and what we’re about. Then look over How to Ask and How to Answer a question to see what makes a good query here, and how best to frame it. We do ask that questions show their effort: show us what you tried and failed; tell us why the straightforward approach won't work; illustrate your question with sketches, screenshots or examples. I'm wondering why can't you just draw the contour? Consider editing your question to show us your efforts. Thanks! Apr 1, 2020 at 15:56
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    Usually that would be a manual operation - using the Bézier Tool (aka Pen Tool) to draw around the image, unless you can first fill the raster image a solid colour in a raster image editor, such as GIMP, but it's probably more trouble than it's worth TBH.
    – Billy Kerr
    Apr 1, 2020 at 16:39
  • Perhaps you could find a silhouette image of a brain instead, then an auto trace would be easy.
    – Billy Kerr
    Apr 1, 2020 at 18:08

1 Answer 1


Using the Trace Bitmap feature provides a number of options. There may be an easier method than this, but consider to adjust the Brightness Cutoff threshold value with the Live Update ticked.

brain trace image

There's a small artifact in the lower left corner, probably left from my hasty edit, but the result is a solid shape. You can then remove fill, add or adjust stroke as desired.

If your computer is slow and/or you have a large number of objects in your image and document, you may find the Live Preview to be burdensome.

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    thx for the help, this seems like a fast method. Apr 2, 2020 at 12:10

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