Welcome to the Onshape forum! Ask questions and join in the discussions about everything Onshape.

First time visiting? Here are some places to start:

Looking for a certain topic? Check out the categories filter or use Search (upper right).
Need support? Ask a question to our Community Support category.
Please submit support tickets for bugs but you can request improvements in the Product Feedback category.
Be respectful, on topic and if you see a problem, Flag it.

If you would like to contact our Community Manager personally, feel free to send a private message or an email.

Best Of

Why is my circular pattern not defined?

I am new to Onshape, so please pardon me if this is a dumb question. I am trying to create a 2D circular pattern about the origin in a sketch. I am starting with a black defined element. When I set all the parameters and click on the left mouse button the pattern appears as expected, but all of the elements in the pattern are blue (undefined) except for the original element. I thought that I must have done something wrong, but then I watched the tutorial video and the same thing happens in the tutorial video. How do get the elements in my pattern to be black (defined)???

arthur_rudick

Re: Why is my circular pattern not defined?

You need to make the center of the pattern coincident to something (seems like you want the origin in this case). If you drag the pattern slightly you should see a blue point which is the center of the circular pattern. Add a coincident relation with the origin.

S1mon

Re: Tangent Mate is bistable (and I don't need it to be)

I also fully agree. A tangent mate in a 3D model (maybe other than in a sketch) could refer to surface normals in order to make a tangent mate stable by default. That is what I would expect.

martin_kopplow

Re: Perforate a cylindrical shape

Hey Mark. Here is a method you might be able to use to perforate your part. Playing around with the shape (shapes?) in sketch 1 might get what you want. The Circular Pattern feature allows the removal of pattern instances should the pattern fall upon an edge of the part, which I assume would be undesirable.

Beyond using Onshape's native tools. Evan Reese created a custom feature you might be able to use. Check out this post for a discussion, link to the feature script and a video of using the feature script. - Scotty

robert_scott_jr_

Re: Best approach for complex surface shape - Loft/Sweep/Bridging Curve/ other?

https://forum.onshape.com/discussion/comment/123889#Comment_123889

@S1mon @jelte_steur_info

thank you both for the really good feedback. I was able to (after quite a bit more hours of work) a workable copy. However, I am going to review your sketch Jelte and see how you did it.

I am having issues understanding the sketches not being constrained. I was under the impression that once the shape snaps are used, and the sketch enclosed, or finished, it is constrained. I must be mis-understanding how to lock its contents in.

nonetheless, thank you both greatly!

jerome_stancil

Re: Best approach for complex surface shape - Loft/Sweep/Bridging Curve/ other?

I think something along these lines is how the part is built up.
In general: please make sure sketches (like sketch 7) are fully constrained. the lack of tangency/concentricity etc is causing downstream issues quite quickly:

https://cad.onshape.com/documents/ccb37699191c84712fb79624/w/823c67f8bc41e015beb37e33/e/23b5ff33b5e667de837a2c93

jelte_steur_info

Re: Best approach for complex surface shape - Loft/Sweep/Bridging Curve/ other?

This is a fairly complex set of features to model accurately. In general, you want to break down the shapes into surfaces with similar curvature and work from larger to smaller surfaces. It doesn't look like much in the more difficult area has a constant wall. You'll likely need to model the core and cavity sides somewhat independently.

I see a bigger transition surface, with some flanges on the sides that have some complex transitions at the ends. The core side has a conical surface coming off the round mounting feature, and then it has a large transition to the flat flange. The conical surface could be a partial revolve or semi-circular sweep. Next I would do some lofts or boundary surfaces for the major surfaces, and then work my way through the smaller more detailed bits.

Do you have multiples of this part that you could scrap one or two and cut some sections on a band saw? Can you do a 3D scan with an iOS device or a dedicated part scanner? Can you take some careful orthogonal photos with a really long lens to reduce parallax? Any of these methods would help give you more ground truth to start from. Calipers are only going to get you so far with shapes like these.

I noticed that a lot of your sketches are unconstrained. I would be careful with that, as you can easily end up with weird issues if you edit something early in the model and things aren't fully constrained or intentional.

S1mon