cut sweep from revolution :FIXED:

[quick61]

@quick61

I see you used two circles from draft to make the sweep, but I can't see how you got your orientation to make the draft circle on the revolution. Honestly I didn't even know circles could be used that way directly from draft, but I'm stymied on how you found the proper orientation.

Oh, that's easy.

First I created the revolution in Part Design. then I switched to Draft Workbench because I find it a lot easier to use for these types of operations than Sketches are. (maybe it's just me?). First In top view with Working plane set to Top I created a circle that was snapped to the midpoint of the outer seam of the Revolution. Didn't matter what the radius was, as that can be changed later on. Then I selected the end face of the Revolution and clicked on the Working plane to set it to that face. Then just center snapped a Circle to that face and snapped the radius to the outer seam. Now I have a circle the same radius as the radius of the Revolution. Then I used Placement and rotated that circle into position on the Z axis. Then it was a simple matter of Sweeping Circle using Circle001 as the Path. Cut then done.

Yes, Draft objects are very useful for Sweeps, Lofts, Extrudes, ShapeBuilder, etc.. Once you figure out the Draft Workbench and all that it can be used for, you'll wonder how you ever got anything done without it.

Mark

[Eric Delang]

First I'd like to thank everyone that has helped to build this great tool and make it available to everyone. Great job! Keep up the good work.

I am having a problem with the "Cut" for an o-ring on the inside of a drive shaft (pipe) to remain working. At some point in the design cycle, it fails to work correctly and the groove that the "Cut" function initially created, eventually disappears.

I've built this part twice, once with a full length center shaft and another time with each section of the shaft being a separate sketch. I thought that subsequent functions being performed on the single shaft part were causing the problem, but the separate sketches design (attached) still has the same problem.

To create the o-ring groove, I create a circle sketch and "revolve" it to create the o-ring (essentially a toroid - btw- I also tried to "cut" a toroid but I couldn't get that to work either). Then I used the "Cut" function and I got my groove. As I added more features to the drive shaft, at some point the groove disappears and I am unable to get it to generate again.

I've tried using the "Boolean" function with changing all the different parameters in including the selection order of the solids, but it makes no difference. I've read through all the Forum discussions related to cutting o-rings or similar issues, but nothing I do seems to make any difference. For what it's worth, it seems that the disappearance of the groove might occur with the creation of the drive shaft splines, but I'm not sure about this since I didn't verify exactly when the "Cut" function started to fail, only that it didn't work after the splines were built.

I am completely out of ideas to correct this. PLEASE HELP!

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6706 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: f86a4e411ff7848dea98d7242f43b7774bee8fa0
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

[chrisb]

First: you replied to a two years old post, there is not much activity to be expected from that side ...

If I look at the dependency tree I see several problems:

Bildschirmfoto 2017-04-20 um 00.36.54.png (66.58 KiB) Viewed 668 times

- On the right side you see cyclic dependencies. That leads (of course!) to problems, and I am not sure how to repair it. Try deleting Pad004 and recreate it.
- You forked your tree at Pad005. I guess Sketch13 shoud be mapped to Pad004. Detach the sketch with "Reorient sketch" (answer the first question with yes, second with no) and remap it to the approprate face of Pad004.
- The cut depending on an intermediate state is another fork.

- I am not sure if you really want several independent objects - as the independent parts of the tree show - or if it should rather be a single line, like the one in the middle from OuterShell001 to HexNut.

The problem with the groove not working was probably due to the fact that you had several states of your object visible at once. When working with PartDesign Workbench you don't have several objects, it is all the same object with additional features. You should have visible only the last state before continuing with the next step.

I strongly recommend to work through some of the turorials on the website - and I really mean work through, not only look at them.

[Eric Delang]

Thanks chrisb.

I did not intend to create cyclic dependencies. Quite frankly, I couldn't figure out how to control the process tree. The software changes the tree seemingly every time I make a new feature. I've tried to modify it but haven't figured out how that works. My intentions were to have it "processed" in the exact order that I created the part, but it doesn't seem to do that. I'll look into some tutorials that might shine light on this issue.

Thanks,

[chrisb]

Thanks chrisb.

I did not intend to create cyclic dependencies. Quite frankly, I couldn't figure out how to control the process tree. The software changes the tree seemingly every time I make a new feature. I've tried to modify it but haven't figured out how that works. My intentions were to have it "processed" in the exact order that I created the part, but it doesn't seem to do that. I'll look into some tutorials that might shine light on this issue.

Thanks,

You're welcome.

• If you only add new elements they are added at the bottom of the tree.
  • In Part Design Workbench if you create a pad or pocket from a sketch the sketch becomes a subelement of the pad/pocket.
  • In Path Workbench, if you make a boolean operation both used elements become subelements of the bool op.
• If you delete an element in the tree, all of its subelements are placed at the bottom of the tree. So the order in the tree does not reflect the construction history anymore.

I don't know how you created the cyclic dependency - and you probably don't know it either - but I think most, if not all, of your problems could be omitted if you make sure to have only the last state visible before creating a new element. You can toggle the visibility by selecting the element in the tree and hitting space. Invisible elements are greyed out. If you are not sure, hide everything and make exactly one visible again.