Turning Sketches Around a Single Axis

[Mr Wahlander]

FreeCAD seems to be a wonderful program! I feel fortunate to have found it.
I am trying to figure out how to rotate a sketch around a single axis (the z in my case)
I feel my question is rather basic.. but I have watched numerous videos and tried searching the forum.
Please forgive me if I’m posting something that doesn’t belong here!
:-/

OS: Mac OS X
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13519 (Git)
Build type: Release
Branch: (HEAD detached at 1a8b868)
Hash: 1a8b868018f45ea486c0023fdbfeb06febc1fb89
Python version: 2.7.14
Qt version: 5.10.1
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/Sweden (en_SE)

I am trying to create a skeleton of sketches, Which I plan to Loft.
I need a ”cupola” with a ”wavy” surface.
I started constructing by making a sketch of the ”flor”-contour in the xy-plane
The following scetches are a mystery….
I made the first one in the zy-plane. When I look in the property field the axix values for x, y and z is 0,58. (hm…?)
When I change the angle (120) the sketch will turn around all three axes. I need it to turn around the z only.

I can rotate the scetches if they are first extruded (picture) but the extruded scetches cannot be used in the loft tool.

I might be on the wrong path all along, is there a better way?

Geeatings from Sweden
Johan

[chrisb]

I made the first one in the zy-plane. When I look in the property field the axix values for x, y and z is 0,58. (hm…?)
When I change the angle (120) the sketch will turn around all three axes. I need it to turn around the z only.

Hi Johan, welcome to the forum and greetings to sweden.
The placement is described by a compound value and not by X,Y,Z and rotations around these axes, that's where the 0.58 comes from.

If you want to turn only around Z axis you can check the "Incremental" switch in the Placement editor panel.

[prandall]

Are you going for something like this. I completed this with Sketcher Workbench and Part Workbench loft.

Selection_652.png (44.51 KiB) Viewed 2107 times

I wouldn't even try this in Part Design WB, The Polar Pattern is slower and it is too picky about which feature you can use. Of course that could just be be my lack of skills.

Here is a better version that shows tree and sketch outline.

Workspace 1_653.png (176.86 KiB) Viewed 2106 times

[DeepSOIC]

Another way of "rotating" sketches is to make a few faces by extruding a XY-plane sketch. Then put your sketches on these faces.

faces-for-sketches 2.FCStd

(18.66 KiB) Downloaded 59 times

Yet another way is to attach a sketch, and then use attachment dialog (attachment offset) to rotate it.

[Mr Wahlander]

Tack snälla ni
!!
Thank you so much from Sweden! I will try all your suggestions. It is indeed true (as I read here and there) that the program has a rather steep learning curve. I look forward to being able to move on from basic things like this.

[chrisb]

It is indeed true (as I read here and there) that the program has a rather steep learning curve.

A steep learning curve means you have to go only a few steps in the right direction and you have reached a new level!

[Mr Wahlander]

Another way of "rotating" sketches is to make a few faces by extruding a XY-plane sketch. Then put your sketches on these faces.

Hello, and thank you for your help, and your patience with a beginner!

I followed your first suggestion and extruded a xy-plane sketch.
I couldn't find the extrude in the dialogue box, only the sketch which was extruded.
I then got the following message:
"Can't map a sketch to support:Some of the selected objects depend on the sketch to be mapped. Circular dependencies are not allowed!"

What could that mean?
:-/
Johan

[chrisb]

This happens when you have already padded the sketch and you try to map the sketch to no matter which face of that pad. You have to take the previous feature in the tree. Making it visible hides the last feature and now you can attach the sketch.

[Mr Wahlander]

This happens when you have already padded the sketch and you try to map the sketch to no matter which face of that pad. You have to take the previous feature in the tree. Making it visible hides the last feature and now you cann attach the sketch.

I'm so sorry ChrisB, I have tried and tried, but I don't understand what it is I'm doing wrong... :-/ Does this look like a correct start? I made a simple sketch with a few straight lines. I then extruded this sketch, and now I'm trying to figure out how to map other sketches on the surface of the "walls". But I only get the previously reported error message... I tried going to the tree and unhiding the sketch. etc. Thank you for your patience... Johan

[chrisb]

I made a simple sketch with a few straight lines. I then extruded this sketch, and now I'm trying to figure out how to map other sketches on the surface of the "walls". But I only get the previously reported error message... I tried going to the tree and unhiding the sketch. etc. Thank you for your patience... Johan

The way you describe is a good one:

- Create a sketch
- Extrude it
- select a face, this is something you might have forgotten!
- create the next sketch, if asked for the attachment mode select "flat face"