Painting on oblique images

v5.8.1

sample data cta abdomen.

Create double oblique…

I have never understood this.

When I click with the paint tool, I do not get a circle.

I might understand this.

But I definitely do not understand why when i drag the circle around, it fills in?

Same behavior with and without masking.

1 Like

Thanks for the reply.

I was aware of this. I’m not sure that it is the exact same issue. It may be. This has always confused me.

I do not understand why when one clicks, there is one segmentation, but when one drags additional pixels are segmented.

I’ve been struggling with this issue for some time. My work around was to drag the roi until it is complete. So I am really iteratively painting away the “artifacts” without reslicing.

When you paint an oblique slice it’s like painting this surface with a roller

because the volume is sliced using an oblique plane.

Maybe we could add a thickness option to the paintbrush, but the solutions suggested by @lassoan (in the page referenced by @pieper) seem to be more correct.

1 Like

May be the Scissors effect could be used for painting in most cases; it already has a free-form and thickness options.

1 Like

That’s exactly it….. I guess the the irreproducibility that I was experiencing was a slight movement of the mouse.

Resampling is an option, but yesterday I was annotating at a bunch of angles.

*** One question, if i resample the volume then annotated on a specific slice, when I rotate back, won’t it have the same result?

I‘ve done a lot of rolling in the past. I was annotating oblique valve planes to be subtracted from another segment and need it to be complete 3d disk. Rolling, fill holes, etc.

I think this is an important aspect, that you want to segment on multiple different oblique directions. In this case I don’t suggest resampling, because every time you do that, you lose some image quality (and segmentation fidelity).

In this case I suggest oversampling the segmentation. I just tried it and it seems to work well for oblique painting:

1 Like