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How to rotate a sketch, using its side as axis?
Posted: Thu Jan 16, 2020 3:04 pm
by ifohancroft
Hi,
I have a FreeCAD document, that has two sketches, each of them looking like this:
- one.png (9 KiB) Viewed 863 times
Together, from the top, they look like this:
- two.png (9.08 KiB) Viewed 863 times
From the right side, they look like this:
- three.png (8.2 KiB) Viewed 863 times
I want to rotate the second sketch so from the side, they will look like this:
- four.png (8.63 KiB) Viewed 863 times
However, instead, when I rotate the second sketch on the X axis by 5 degrees, I get this:
- five.png (8.85 KiB) Viewed 863 times
I presume this happens because the second sketch gets rotated around the middle as opposed to by the side.
How do I rotate it to achieve the result I want?
I will upload the FreeCAD file as an attachment in the next comment.
Re: How to rotate a sketch, using its side as axis?
Posted: Thu Jan 16, 2020 3:05 pm
by ifohancroft
Here is the FreeCAD file:
Re: How to rotate a sketch, using its side as axis?
Posted: Thu Jan 16, 2020 3:26 pm
by bejant
In the Placement widget (not the Placement Properties in the Data tab) first tick "Apply Incremental Changes" to True, then change the Center, and finally do the Rotation.
https://www.freecadweb.org/wiki/Tasks_Placement
Re: How to rotate a sketch, using its side as axis?
Posted: Thu Jan 16, 2020 3:28 pm
by papyblaise
hi it's that you went
: you have to type the position of the hinge
Re: How to rotate a sketch, using its side as axis?
Posted: Thu Jan 16, 2020 5:40 pm
by ifohancroft
@papyblaise Thank you! That worked. Not sure why I couldn't get it to work earlier. Btw the right position is 9.525, not 9.75.
@bejant Thank you! Maybe I'm an idiot but I cannot get your method to do anything. I may have a problem understanding how the placement dialog works or something:
1. After I check Apply Incremental Changes, do I hit Apply or Ok?
2. After I have enabled Apply Incremental Changes (without hitting Apply or OK) I change the Y of the center to -9.525.
3. Then I change the rotation angle but nothing seems to move?! I thought maybe there is no live preview and I need to hit OK, however even after I do, there is still nothing changed?! I thought maybe I then need to rotate via the Attachment Angle in the Data Tab but it rotates as if I haven't do anything in the Placement Widget.
What am I failing to understand or do?
Re: How to rotate a sketch, using its side as axis?
Posted: Thu Jan 16, 2020 6:48 pm
by Vincent B
A easy way is to use a datumplane.
choose an edge and make a datumline, make a datumplane with it.
rotate it on the right axle as needed.
Then map a sketch on the datumplane and draw the next sketch.
Re: How to rotate a sketch, using its side as axis?
Posted: Thu Jan 16, 2020 8:45 pm
by papyblaise
A easy way is to use a datumplane.
yes but the question is not to draw a sketch as an angle , but I have two sketch on the same plan : how to rotate one around a line of the second
Re: How to rotate a sketch, using its side as axis?
Posted: Thu Jan 16, 2020 9:09 pm
by Vincent B
La fin justifie les moyens.
Re: How to rotate a sketch, using its side as axis?
Posted: Thu Jan 16, 2020 9:30 pm
by ifohancroft
@GlouGlou Thank you! That's a good idea too. I keep forgetting about datum planes.
@papyblaise What GlouGlou said also works for me. I should have probably posted what I want to do that I need this step for.
I have found an easier way that works for me. Sketching the side profile, then padding towards the back and then creating the holes.
Now I need to figure out an easy way to also create such "strips" to the sides, with also 5 degree angle between the "strips". I have figured out how to do it but after I finish it, I need to check if there is a better way.
Re: How to rotate a sketch, using its side as axis?
Posted: Thu Jan 16, 2020 11:04 pm
by bejant
ifohancroft wrote: ↑Thu Jan 16, 2020 5:40 pm
1. After I check Apply Incremental Changes, do I hit Apply or Ok?
No, just tick the Apply Incremental Changes..." tick box to True (do this first).
ifohancroft wrote: ↑Thu Jan 16, 2020 5:40 pm
2. After I have enabled Apply Incremental Changes (without hitting Apply or OK) I change the Y of the center to -9.525.
I think you want to make Y = 9.525 (no negative sign).
ifohancroft wrote: ↑Thu Jan 16, 2020 5:40 pm
3. Then I change the rotation angle but nothing seems to move?! I thought maybe there is no live preview and I need to hit OK,
You should be changing the Attachment Offset using the Placement widget, don;t think I was clear before. In the Placement widget, above the "Apply Incremental Changes..." tickbox, change the Axis to Y and then change the Angle field to whatever angle you need. There is a live preview so you should see the Sketch rotate as you change the Y angle value.
I trued to use your file but got a message: "Cannot compute Inventor representation for the shape of (
(the file name)" so I just tried using my own new file.
OS: Ubuntu 18.04.3 LTS (ubuntu:GNOME/ubuntu)
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.19.
(dated 2020-01-05)
Build type: Release
Python version: 3.6.9
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)