How to extrude on a curved surface

Hello all, new Shapr user. I am trying to cut a panel line on a curved surface, I have projected the panel onto the curved surface, however it doesn’t allow me to add negative extrude to it for some reason? Am I doing something wrong?

As you can see from the picture attached, I have successfully indented a the lower panel on a flat surface without any issues.

Any help would be greatly appreciated.

I think your problem is where your panel is across the transition between the curved surface and the flat surface.
I get the same issue, if I draw a similar profile.
I can surface offset as long as it does not include the transition line.

I just tried, could not make it to fail.

In some more complex situations when going all way trough fails I found that a fallback to create a body and then subtract may succeed.

I always try to make clean cuts and merges, avoiding creating (to) complex result. In the example the sketch unnecessary tangens the surface could this make a difference?

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Thanks for the reply, I seem to have figured how to get it to work, I think I may have messed up the step while doing the projection, initially the projected faces was done one by one, have just realised you can actually project onto 3 faces simultaneously and that seems to have solved the issue.

I did the same sketch and solid again, and this time it worked no problem.
:rofl: