Sweep Unexpected Twist
Sweep Unexpected Twist
(OP)
I'm trying to create a basic 'rib' along the top surface of a part. However, Solidworks can't seem to correctly resolve the path and I get "Sweep resulted in topologically invalid body" error.
I have the path as a 3D sketch along the surface of the part, and the profile, a simple square, perpendicular to the path. When the sweep is created, it begins to unexpectedly twist as it moves along the path around a corner and over a curve, as shown in the pictures. I'm not sure why this is occurring, but I suspect this is causing the error, and even if it's not, it's not what I intend.
For 'options' I have Orientation set as "Follow Path", and Path Alignment type as "Minimum Twist". I have tried just about every other combination of setting without any improvement.
Any ideas on how I can resolve this?



I have the path as a 3D sketch along the surface of the part, and the profile, a simple square, perpendicular to the path. When the sweep is created, it begins to unexpectedly twist as it moves along the path around a corner and over a curve, as shown in the pictures. I'm not sure why this is occurring, but I suspect this is causing the error, and even if it's not, it's not what I intend.
For 'options' I have Orientation set as "Follow Path", and Path Alignment type as "Minimum Twist". I have tried just about every other combination of setting without any improvement.
Any ideas on how I can resolve this?






RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
Jeff Mirisola
My Blog
RE: Sweep Unexpected Twist
Perhaps I'm just approaching this problem wrong. I want to add a 'ridge' or 'rib' along the surface to a joining part can fit snugly on it. How would other people go about adding this to the part?
I'm trying to use a second curve as a guide curve, but so far not having any success.
RE: Sweep Unexpected Twist
http://help.solidworks.com/2013/English/solidworks...
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
I've been trying to use a second sketch as a curve guide, but keep running into problems such as "too many entities share a point" or some other error. Not sure why, sometimes it works, sometimes it doesn't. I can re-sketch everything and it will work and then I try something else and it all falls apart and I have to start over. It's like the nexus of the universe in here!
RE: Sweep Unexpected Twist
http://help.solidworks.com/2013/English/SolidWorks...
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
That doesn't look like a thickened surface. A thickened surface should create an equal cross-section. What you show looks like an extrude with a direction vector.
Can you post the actual SW parts (or simplified versions) to work with?
RE: Sweep Unexpected Twist
I attached the file so you can play around with it. Thanks!
RE: Sweep Unexpected Twist
Hopefully the attachment will give you a good start.
RE: Sweep Unexpected Twist
Could you run me through the steps you took a bit. What was the Surface-Offset operations for?
RE: Sweep Unexpected Twist
Surface-offsets 1 & 2 were create to be the trimming planes for the Zero-offset surface, but they had to be extended first.
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
In the interest of seeing how few steps this could be done in I modded your Sketch 1 and took out the surface extend to simplify a bit further. As a thought exercise I'd be interested if anyone gets it down simpler than this. With CBL's method its down to 5 items in the model tree, including the new reference plane.
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
I Have a hunch that it could be done with 2 features, using just a boundary surface and the intersect, Possibly 1 with a boundary boss/Base feature. Both of those would require additional sketches though, so there'd be more work involved than this method.
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
Thanks for all help and effort from everyone. This has been a really interesting lesson.
RE: Sweep Unexpected Twist
Clearly this 'ridge' needs to interface with another piece. So now I'm looking at doing the inverse, rather than an extruded shape, it's a cut shape into the part. I've been playing around with it, but putting surfaces inside another part is somewhat pointless. What's the best way to proceed with this? Thanks!
RE: Sweep Unexpected Twist
Or you could use the Insert > Part function to insert the part with the rib, into the part needing the recess (multi-body part), and then use the Combine > Subtract method.
Or you could use the Insert > Part function to create a multi-body part (of the parts without any rib or recess) and then use the Rib tool twice (once on the inside edges & once on the outside edges) to create the rib and recess ... maybe.
RE: Sweep Unexpected Twist
RE: Sweep Unexpected Twist
Find a local SWUG (SolidWorks User Group) in your area. Your VAR should be able to help locate one for you. If one exists there will be other SW users there who should be able to help you. Your VAR should also be able to offer some training.
The Combine tool is only available in multibody parts ... not assemblies.