Is there an "inverse pocket"?

[CarlH]

I apologize if this is already covered on here, but I couldn't find it. Maybe I'm not using the right terminology. At any rate, maybe someone would be kind enough to help a brand-new user out...

Where I am currently stuck- I want to make a restrictor / spacer out of 1" bar stock, and I managed to make the basic shape, but now I would like to put a hex on it for installation with a 22mm socket (it will eventually have m18x1.5 threads inside and out when I figure that part out later). I created a sketch of a hex on the top surface, and want to remove all material "outside" of the sketch (inverse pocket?) as the hex is projected downward. The "reverse" checkbox within the pocket tool doesn't seem to do it (that seems to change if it is pocketing "up" or "down"). I've been mainly using "part design" workbench. Do any of you know a simple way to accomplish this task that you would be willing to share?

OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.15.4671 (Git)
Branch: releases/FreeCAD-0-15
Hash: 244b3aef360841646cbfe80a1b225c8b39c8380c
Python version: 2.7.8
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

[DeepSOIC]

Hi!
Staying with PartDesign, the result can be achieved by making another big profile in the sketch, to remove material in a pipe-like fashion.

spacer inverse pocket.FCStd

Made with v0.17, hopefully the file will open in 0.15...

(27.03 KiB) Downloaded 189 times

Alternative is to Part Extrude the hex sketch, and then do Part Common.

OS: Windows 8.1
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.7419 (Git)
Build type: Release
Branch: master
Hash: 6b1c433807dddb0c924e2869df49df534b270340
Python version: 2.7.8
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

[bejant]

Made with v0.17, hopefully the file will open in 0.15.

I had to try and it opened OK with:

OS: Ubuntu 14.04.4 LTS
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.16.6698 (Git)
Build type: None
Branch: master
Hash: ca7c5d31a4d61f32a25b71025b14641a6e378328
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

[NormandC]

Is there an "inverse pocket"?

Coming from a Solid Edge background (it's the CAD software I use everyday at work), I miss this option, as well as open profiles...

In SE this is called "reverse direction".

[jmaustpc]

Is there an "inverse pocket"?

Coming from a Solid Edge background (it's the CAD software I use everyday at work), I miss this option, as well as open profiles...

In SE this is called "reverse direction".

Hi Norm
How does it know where to stop? Does it cut to infinity? If so, I can think of cases where that could give unexpected results. So how does it work in Solid Edge? Does it use the face your sketch is attached to, as a bounding box for the operation?

[NormandC]

How does it know where to stop? Does it cut to infinity? If so, I can think of cases where that could give unexpected results. So how does it work in Solid Edge? Does it use the face your sketch is attached to, as a bounding box for the operation?

Yes, it cuts to infinity on the sketch plane, depending on how your open profile is drawn. A straight line is a simple case. When applying a Cutout (Pocket), the system asks for a direction, and you have an arrow in the 3D view you can orient, you click on one side of the profile or the other, then you go to the next step, defining the Cutout depth.

If your open profile is an arc tangent to an external edge, you may get unexpected results. In some cases the Cutout "continues" the arc on the body and your solid gets cut unexpectedly... I'm struggling to describe this, so I'll try to make screen shots (or maybe a video) at work tomorrow.

When you know its quirks, it is very, very efficient, because your sketch is so fast to create. AFAIK Solid Edge is the only CAD software that supports open profiles for 3D features, but I may be mistaken, at least that was the case when I was keeping up-to-date with the commercial CAD offerings.

[jmaustpc]

If your open profile is an arc tangent to an external edge, you may get unexpected results. In some cases the Cutout "continues" the arc on the body and your solid gets cut unexpectedly... I'm

Sounds like OCE,

Yes, it cuts to infinity on the sketch plane,

I suppose you would have to be careful then when working on a complex solid, not to cut of a higher point of the solid.

[NormandC]

I suppose you would have to be careful then when working on a complex solid, not to cut of a higher point of the solid.

Yes, in such cases you have to add geometry to your open profile so it doesn't cut where you don't want it to. Still, it remains faster than creating a fully closed profile.

[steveinjava]

CarlH, I am not very experienced as yet with FreeCAD but I had exactly this requirement and (IMO) it is easy to achieve.
Having created a sketch with the required shape on it- select the original parts face OUTSIDE the new shape. Then hit pocket and choose your depth. I hope this is what you needed- if so and I am right- then it needs more publicity as I see via google that it is not known about.

[kisolre]

This will cut only that shape. What if there was something bigger down the pocket? A big rectangle around the desired shape including all existing geometry is still the best option until somebody decides to implement "common" feature in part design.