Mesh to Solid -> Then combine/cut another solid

[kzydave]

I have imported a mesh into a new design, reduced the facet count (8300) and then convert mesh to BRep. This is all fine, but I wish to then use this new solid from mesh to combine/cut from another solid. You can see from the screencast I have a large block I wish to shape the bottom from the mesh solid so its. half flat and half mesh face.  I can't actually combine/cut the bodies so that I can then use the top half. You can see from the second half of the screencast I have already done it once a few weeks ago, just can't seem to work out how it did it the first. time.

Adding some gauges to my new Swift Sports. 🙂

have a Prusa MK3S so will print from black PETG.

Attached the Design I'm trying to play with. 

What am I doing wrong here? is there another way to approach what I need as the base?

[davebYYPCU]

Close, it’s Extrude > Cut, make the profile big enough to trim the complete lower section away.

Might help....

[kzydave]

I may have also selected the solid rectangle object, then tried to split the body by then selecting (left click->drag) over the bottom part of the new Solid/mesh facets. Fusion goes into a memory overrun.

[kzydave]

So I found if i turn history off and then select Combine/cut....

Select the box as the body from left tool menu

Select the BRep body from the left tool menu I can then select OK.

The error I then get is: no intersection between target and split tool

[davebYYPCU]

Works for me, 

Might help....

[laughingcreek]

@kzydave -The combine tool only works on solids, not surfaces.  the tool you used before was Split Body.