How to recess a rectangle on a cube exactly where I want it?

[Cambriabill]

I have a cube and want to recess a rectangle 4 mm and place the rectangle exactly 10mm from the left edge and top edge of the cube.

[bejant]

Hi Cambriabill and welcome!

I have a cube and want to recess a rectangle 4 mm and place the rectangle exactly 10mm from the left edge and top edge of the cube.

In FreeCAD we usually the rectangle first, then create the recess. Starting with a Cube, select the face onto which you'd like to create the rectangle and recess, then in the Part Design WB click the Create Sketch tool:

and Sketcher a rectangle using this tool:

Click the Create External Geometry tool:

and select either the top or the left edge of the Cube to create a magenta line segment. Use an endpoint of the magenta line segment and the upper left corner of your rectangle as you create the 10mm Distance Constraints:


You should end up with something like this, but without the recess:

20170501a.png (7.11 KiB) Viewed 1537 times

Define the size of the rectangle by applying the same Distance Constraints to a horizontal and to a vertical edge so that the Sketch is Fully Constrained (the white geometry will turn green, and Sketcher Solver will display a message informing you that the Sketch is Fully Constrained).

Close Sketcher and select the Pocket tool:

to create the recess.

Here is the file if you'd like to have a look:

20170501a.fcstd

(17.09 KiB) Downloaded 29 times

I used:
OS: Ubuntu 16.04.2 LTS
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.16.6707 (Git)
Build type: None
Branch: releases/FreeCAD-0-16
Hash: 5465bc47c95db45e0be85dc0e2872419efadce0f
Python version: 2.7.12
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

[Cambriabill]

Thank you very much for the detailed reply.
Cambriabill

[Stars_Coach]

I would appreciate some help finishing the last step of the instructions provided in this thread!
I too am trying to do this exact thing.

After using the Create External Geometry tool and select the left edge of the Cube, I get the Magenta line in my rectangular sketch, BUT cannot perform the last step listed below.
"Use an endpoint of the magenta line segment and the upper left corner of your rectangle as you create the 10mm Distance Constraints:"

How do I "select" the endpoint of the Magenta line? (sometimes the mouse pointer turns into the little table looking icon representing the Create External Geometry tool.
Obviously, I'm missing something.
Thanks

[NormandC]

Hi Stars_Coach,

(sometimes the mouse pointer turns into the little table looking icon representing the Create External Geometry tool.

I believe you have not ended the command, it stays active. Simply right-click to terminate the command, then you'll be able to select an end point.

[Stars_Coach]

You are correct in that I did not end the command (didn't know I needed to being a newbie and all).
Thanks kindly for the quick solution!

[NormandC]

Glad I could be of help.