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.
Options
Comments
So here's the idea, create a tailpiece for a motorcycle:
I prefer working with an industrial designer to come up with the looks, in this case I did it:
There's a tremendous amount of work that goes into the 1st loft.
The 2nd loft:
I don't think bridge curves existed back when I did this. I do tend to play with magnitudes to control my blends and I use the surface highlighting to control the smoothness.
Highlights to control blends:
This actually took some trial and error. There's a tight corner in the upper right that transitions into a body blend. It looks good on the actual part which is printed nylon but it's a fairly small part. I don't use curvature combs or any edge controls and focus on the surface highlights. I'm not saying this is correct it's just currently how I do it.
Side trim to tuck into seat:
There's always tons of prep work to build up for one trim feature (while you're at it, we need a trim feature).
And then there's the other side:
A lot a people say you can't do this, but you can.
I don't want to control both sides when designing, build one side and then mirror.
Some would object to conditions at the mirroring plane, I don't have those issues.
In this design, I have a feature that'll span across the mirror plane.
Spanning center feature:
You can control the blend between the 2 halves, but it requires planning/forethought.
I brought the tank detail down into the tail piece.
Tank detail:
All surfaces and a ton of scaffolding:
Solidify:
I rarely use shell or offset.
I find it better to build inside details manually for: ease, speed & control.
I used enclose, as you know, it forces solidification which you have to plan for. I have an IR issued to fix this but will use mutual trim in the future.
Then there's a ton of solid features to finish things up.
This is a common workflow that I use when creating organic shapes. Surfaces differ from solids in the amount of prep work that goes into the construction of a single surface feature. With solids it's one sketch and with surfaces it's 20 scaffolding surfaces to generate the edges needed for the final surface. Scaffolding is my name for the build up of a surface. You won't find any reference to it in technical manuals.
This model is fairly robust. I put the design on my website a while back to allow someone to design their own tail piece. I controlled magnitude vectors with html input so people could change the curvatures of a custom tailpiece and my website updated to reflect the changes.
It's surprising how few do surfacing.
Thank you for the detailed explanation. This is very helpful. And I also call those reference surfaces scaffolding
I agree, there needs to be more education about designing injection molded parts. It should probably start with how an injection molding machine works.
You can create multiple injected parts inside OS. I'd probably do it inside a partstudio because all parts could share common references easily. It'd be a long feature list and you'd would have to manage the tree otherwise things would become chaotic. If you have multiple injection molded parts I'd absolutely do them in a part studio so I could easily share datums between parts. I'd also build an assembly so I could check the movement between parts. Top, bottom & battery door snap latch; I've done this a dozens of times and use a another assembly to stuff in the electronics. I'd avoid incontext (or designing in the assembly) because moving parts mess up common references. An easy way to think about a part studio is having incontext without any moving parts. With multiple injection molded parts I think OS could do a very good job. Give it a try next time and let us know how it goes.
If you have a production injection molded part with 100's of functioning features, the model would be complex. One of the problems I see is that people are just stacking features on top of one another without reordering creating logical groupings of features so they end up with a long list of un-maintainable features. I have no idea how these guys handle change and I believe they start over.
I'm printing most of my parts today because I don't have the volumes to justify making an injection part. I've printed qty 2 of the part tailpiece and that's probably it. I do design a lot of stuff and make qty 1 of a most my stuff. With nylon, flexural modulus and some FEA you can design snaps that work and a lot of cool stuff. I don't worry about drafts, undercuts & slide shutoffs any more and I don't miss it. Designing printed parts is a lot easier than injection molded parts.
Can you post a picture of one of your complex parts?
Thank you for sharing your process and the examples.
Thanks for showing these, I wish I could see your feature tree and would love to see how you setup your datums and control structures. Can you share your pro/e model?
I'm supposing skeleton surface model translates to a knitted surface body? I'm not certain the word "knit" is used any longer. In onshape you just boolean a bunch of patches together to form something. I'm not sure what it's called now.
Boolean patches create what?
My pro/e understanding, the word "skeleton" was a top level assembly structure to help bring order to large assemblies. I'm sorry but my pro/e knowledge has rusted about 25 years. I'm definitely interested in how pro/e controls plastic part designs.
I've seen guys go from surfaces --> solids --> surfaces -->solids which I consider bad form and the result of a snowball of features. There's a lot of that going on out there. Does pro/e stop that workflow? Once you convert your skeleton to a solid, can you go back to surfaces?
In onshape I have a habit of creating control features out of surfaces, I change their color to transparent yellow and leave them in the surfaces folder. At the end of a project, the surface folder contains only control surfaces used in the project. A temporary surface that's not a control object is deleted after use keeping the surface folder containing only control structures. I manage the surfaces in my surface folder. This is something I do. If you want to know how something's controlled, you just show the surfaces folder then you can easily find the control and drill down to the specifics on how a feature was created.
billyCAD 101 control surfaces:
We don't have dedicated control structures and I make do with what I have, I'm not complaining, its working fine. I gave up on datums & axis many moons ago due to the fact they don't translate. My solidworks models came into onshape with all control structures (because they're surfaces) which really helped when migrating data into onshape. I've been using surfaces for datums for a long time. I had a complex non-planar parting surface which was translated into onshape making it managable to continue. There are things that are almost impossible to recreate from a translated data set. If you use surfaces, which do translate, in the new system, you can continue the design in your new CAD system.
Have you ever exported your pro/e to another CAD system to see what you get?
If you have a current pro/e plastic assembly that's not under NDA, if you can step it over to me, I'd love to poke around and see what I receive. Just PM me and I'll give you my email address.
Could you have it remember the previous boxes for merging and making solid please?
IR for AS/NZS 1100
Done https://cad.onshape.com/documents/342ea79aa4fd6b12b9863cc4/v/3f23972ad197d54c32e40df7/e/56b1ebc53519161a34c02cea
Making solid was remembered before this.
IR for AS/NZS 1100
Website: ovyl.io