Some Extrudes not working

[tranq006]

Hello All,

Still working on these lake contours. Now I project the meshes to a sketch which seems to improve the speed for doing the extrudes. However, some contours (see screencast) still get an error when trying to extrude, and I don't understand why as they seem like simple curves.

[davebYYPCU]

No screencast, 

Extrudes are working, but with 2 blocks overlayed, was hard to tell.

Might help.....

[tranq006]

Hi there, please see my Screencast here

https://knowledge.autodesk.com/support/fusion-360/learn-explore/caas/screencast/Main/Details/c149257...

[davebYYPCU]

I an not surprised Fusion is having trouble.  When I downloaded the file, 

the bodies folder has a good number of surface bodies, and 2 copies of the block, all overlaying in the same place.

The error message is correct, it can’t tell if you are cutting through the surface body, solid body 1, and or solid body 2, or all 3 at once.  Closed body folder is not helping.  

Select either the sketch or one of the body faces - again which one will confuse the heck out of a computer, but humans know what you want.

Hide the bodies you don’t want to alter, select just the sketch region, and try again.

Might help....