Trim to surface of a revolve

dan_cummins

I am basically generating a revolve that looks like a baseball bat.....easy enough.  I then want to flatten two parallel cheeks of the bat.  I would like the revolve surface and the cheeks to be one surface.  I would like the ability to fillet between the revolved surface and the cheeks.  So I generated the revolve, and to make the cheeks I split/cut the revolve with two parallel planes and cut off the cheeks.

I need to know how replace the cheeks I sliced off with a flat surface......I can draw a rectangular sketch on the cheek plane, but I do not know how to trim to the edge of the revolve cheek cut.

Thx in advance!

DC

billy2

DC-

You're talking surfaces and OS doesn't have these functions built in yet. You can extrude surfaces, split surfaces and maybe a few more things that I don't know about. You can not knit or un-knit surfaces and you can not promote a water tight manifold that's been knitted into a solid status at this time. This will be coming, just not today.

One surface to represent both your flats & revolve, that will never happen, math won't allow it. They'll always be multiple surfaces knitted together.

The same goes for making a corner in a spline:


Above I have 2 lines making a corner and then I try to draw a spline on top with a corner. Can't be done unless you have an infinite number of nodes, at that time your cpu would give up and the system would hang.

However, you can make a corner with 2 splines, and that's true with 2 surfaces. 

Since surfaces are made from splines, things you can do with splines translate into things you can do with surfaces.

Bottom line, surfaces are coming and this shape will be far easier to create. Today you'll just have to fudge it with solid cuts & revolves.

dan_cummins

andrew_troup

@dan_cummins
Is there a reason you are starting with surfaces, rather than a solid revolve (with an interior cavity), a solid extrude remove (one feature with two rectangles would flatten the cheeks) and then fillet the resulting solid?
Onshape is currently a lot more capable in solids than in surfaces, and a shape like this seems to lend itself to solids, to my way of thinking.

andrew_troup

@dan_cummins

I probably should answer the question you actually asked, because the answer may be helpful in general, if not in particular.

If you are wedded to surfaces for this job (and there may be a reason I'm unaware of, or a wrinkle I've overlooked) you could do a 'Replace Face' to replace the not-flat cheeks* with the plane #1 or #2 you'd prepared earlier.

Don't be misled when "Replace Face asks for a face or surface: It will accept a plane instead, and in general this sort of undocumented permissiveness (not mentioned in Help, either) tends to be true for Onshape

I would probably model this as a 180 deg revolve, and deal with one cheek only, then mirror the resulting solid, to cut down the superfluous features and be certain of a symnmetrical result.

* For the benefit of others (and initially I was mystified too, because the graphic does not make the cheeks appear hollow)
Looking at the tree, and taking the OP at his word when he implies that the revolve is a surface entity, rather than a solid one: the side cheeks appear to result from thickening the outer surface.
Consequently (if I have guessed right) they are normal to the local face adjoining the edge they share with that face.
Hence (I assume) they are hollow.

dan_cummins

Discovered the issue.  My revolve profile was not closed on one end, so OS would only let me generate a surface.  Close the end in sketch, and boom, I could revolve as a solid.  I used the offset planes to split fuse, and I am all set.

I keep having to remember, if it gets to hard, I must have missed something simple......

Thx!

DC

billy2

DC-

You're talking surfaces and OS doesn't have these functions built in yet. You can extrude surfaces, split surfaces and maybe a few more things that I don't know about. You can not knit or un-knit surfaces and you can not promote a water tight manifold that's been knitted into a solid status at this time. This will be coming, just not today.

One surface to represent both your flats & revolve, that will never happen, math won't allow it. They'll always be multiple surfaces knitted together.

The same goes for making a corner in a spline:


Above I have 2 lines making a corner and then I try to draw a spline on top with a corner. Can't be done unless you have an infinite number of nodes, at that time your cpu would give up and the system would hang.

However, you can make a corner with 2 splines, and that's true with 2 surfaces. 

Since surfaces are made from splines, things you can do with splines translate into things you can do with surfaces.

Bottom line, surfaces are coming and this shape will be far easier to create. Today you'll just have to fudge it with solid cuts & revolves.