Trying the pocket command: "Cannot use this command..."

[rek]

i want to put a pocket all the way through a fusion of a few bodies. FreeCAD 0.19

fist I select a face on the object and start sketch mode, but it needs a reference, so i select the recommended one

first_i_tried_to_create_a_sketch_on_this_face.jpg (78.69 KiB) Viewed 1775 times

secondly this happens, not a clue why.

second_this_weird_thing_happened.png (21.08 KiB) Viewed 1775 times

thirdly i proceed with sketching a circle

thirdly_i_draw_a_circle.jpg (74.05 KiB) Viewed 1775 times

finally, no pocketing is allowed.

and_try_to_pocket_then_this_error_message.jpg (74.6 KiB) Viewed 1775 times

The situation is so complicated, too many questions, can't think of the right one.

Want pocket. How do? (project file attached)

Also, I am trying to use the "Dynamite Plunger" tool to 'create an edge linked to an external geometry' and it does not appear to be able to 'see' the sketches I'm trying to point the tool at. I want to try and put some kind of guides in place so I can be as precise as possible while placing the pocket. I need a pocket and not a hole because I am going through two different sketches at once, made of two round parts that are stacked:

[rek]

two_stacked_round_bodies_one_pocket_through_them.jpg (48.15 KiB) Viewed 1740 times

this will be a 3d printed part with m4 screw holes. I used a fusion command to hold the pieces together because i did not know a way to extrude a shape from an already existing shape like Sketchup's push-pull tool would do.

but after a part-fusion operation has been done, it seems non-trivial to apply a pocket over that.

my next try will be to attempt to draw a cylinder pad where the pocket should go, and try to do a boolean cut operation.

alright, that didn't work. and FreeCAD crashed while trying.

[Willem]

In sketch001 is a redundant dimension of 96 mm, the solver did not see this and it prevented the sketch from placing in X and Y direction.
On the Pad you only need 2 fillets of 5 and 10 mm, doing all fillets separate is not wrong but the file is better to read when you combine them.
Design the whole thing in 1 body, making 5 separate body's and fuse them is wrong.
Here is your file reworked

[Willem]

In sketch001 is a redundant dimension of 96 mm, the solver did not see this and it prevented the sketch from placing in X and Y direction.
On the Pad you only need 2 fillets of 5 and 10 mm, doing all fillets separate is not wrong but the file is better to read when you combine them.
Design the whole thing in 1 body, making 5 separate body's and fuse them is wrong.
Use mirror function for identical parts.
Here is your file reworked

[Bance]

Try Tutorials

[rek]

In sketch001 is a redundant dimension of 96 mm, the solver did not see this and it prevented the sketch from placing in X and Y direction.
On the Pad you only need 2 fillets of 5 and 10 mm, doing all fillets separate is not wrong but the file is better to read when you combine them.
Design the whole thing in 1 body, making 5 separate body's and fuse them is wrong.
Use mirror function for identical parts.
Here is your file reworked

Thanks. I wonder what you mean about designing it as one body, I can't imagine how to do that. For example, how do you transition from a small cube to a large cylinder in one piece?

[Bance]

Try one of these Tutorials

PartDesign_AdditiveLoft

[rek]

great food for thought. will of course check that out but I am dwelling on the very first tutorials.

I thought lofts were for gradual transitions, didn't know they could be used to make a cube abutted against a cylinder out of one sketch. I suppose it could be interesting to see what the minimum transition zone could be verified. But either way, it does seem that to make a loft transition between a rectangle and a circle, you'd still need at least those two sketches anyway so I wonder what the advantage would be to lofting such a transition. Shouldn't a pocket be able to be made to go through a boolean-fused compound part?

[Bance]

Which tutorial are you doing and where are you stuck?

[rek]

Which tutorial are you doing and where are you stuck?

I was doing the "try stuff on your own now" portion of the first tutorial https://wiki.freecadweb.org/Creating_a_ ... PartDesign

I got stuck on a few things, having forgotten that I was instructed in the tutorial to try the Driver/Reference modes, and forgot I left Reference mode on and it caught me by surprise. I will try the next tutorial, and thank you very much for the help.

The great news is that I cris-crossed two cylindrical pockets through this tutorial piece and it sliced perfectly in Prusaslicer. It's for this reason that I am pursuing FreeCAD with a degree of intensity at this time.