a part with multiple bodies - how to cross reference in between?

[behn66]

Dear all,

I do have a generic question please, which belongs "create an edge linked to external geometry" when having multiple bodies.

As seen in the attached drawing I do have 2 gears and I want on both gears a identical-sized rectangular pads (called Box1 and Box1-clone) - orthogonal positioned together.
I do have attached a fcst-file how it could look like., but for sure my solution to this sounds suboptimal, hence my question how I could have done it better please:
- I failed to use the "parallel" constraint between the different pads on different bodies I had to manually adjust the angle to 7.2 degree to ensure both pads are aligned orthogonal together.
- I failed to use the feature "create an edge linked to external geometry" between the different bodies. As such I had to manually size the second pad identical to the first.

I have been using a single part and each gear mapped to a different body. Not sure if this is the correct way to start here at all.

Kindly let me know how could have done it better to allow referencing an angle between different bodies or make use of the "create an edge linked to external geometry" between different bodies. Maybe my approach of placing two bodies in the same part was already the first wrong step I did...

OS: Ubuntu 16.10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.10064 (Git)
Build type: None
Branch: master
Hash: d7ed8c4383f394f64dd9314eefa00efae02fb32f
Python version: 2.7.12+
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17


many thanks

christian

[DeepSOIC]

Hi!
My usual approach to such situation is master sketches. Something like this:
1. You go to Sketcher workbench, and create a sketch outside of Bodies.
You draw some very simple geometry to later use for alignment of your rectangles.
2. Then, you add ShapeBinders of this master sketch into each body, and reference the shapebinders by linking to them from sketches as you normally would.

Alternatively, you can create links across bodies directly, if you hold Ctrl when in tool "Create an edge linked...".

Alternatively, you can also create a shapebinder from one body to another.

[DeepSOIC]

Oh, it looks like you are moving the bodies. If so, there is no way so far to take that angle into account, rather than define it in spreadsheet and reference again and again from various places.

EDIT: looking at your file... no Body is rotated.

[behn66]

Dear DeepSoic,

pressing ctrl to create the links works perfectly for me. This solves mine issue!
I will look as well into the master-sketch idea - this looks promising as well.


many thanks

christian

[NormandC]

Alternatively, you can create links across bodies directly, if you hold Ctrl when in tool "Create an edge linked...".

What? An Easter egg?

Need to remember that one...

[Kunda1]

Alternatively, you can create links across bodies directly, if you hold Ctrl when in tool "Create an edge linked...".

What? An Easter egg?

Need to remember that one...

Maybe we can have an easter-egg page on the wiki?

[shaise]

Control click on other bodies does not work for me. Has this feature been removed?

[ickby]

Control click on other bodies does not work for me. Has this feature been removed?

yes

[shaise]

OK, I see it was removed.
Anyway, I tried to use a shape binder (or what i think a shape binder is) and it also did not work:
1. create new body
2. select a face from old body
3. create new sketch
4. select "make indipended copy"
I get a sketch over the copied feature (painted yellow) but I can not reference any of its edges.

shai

[shaise]

OK Found the solution:
I just needed to hide the old body, and now the shape is selectable...