How to bend a part along a projected curve

jason_ryan337

Hi all. I would like to bend an ornate column along a projected curve on a curved surface. I have created a simplified column in the document below and would like to bend it onto the face of the bowl behind it. Is there a way this can be done reasonably? I would like to create a much more ornate column so drawing and extruding it directly on the curve face seems really hard.

If this method seems too difficult, could I instead start with an "unwrapped" flat surface of the bowl and add all of the columns to the flattened surface and then wrap the entire assembly back around the bowl (after writing this, it seems to have the same problem, lol)?

https://cad.onshape.com/documents/86202c50e42847587ee33ffd/w/cc0a2b38dd041a0c369d4ae0/e/1e40f934f2c900c897015652

MDesign

if it’s on a bowl assuming it’s circular. Wouldn’t revolve be adequate?

martin_kopplow

There isn't a post forming process built into Onshape I am aware of. It should be possible to build the part based on geometry taken from the bowl, though, so it gets a shape that depends on and follows later edits to the shape of the bowl.

What you were asking for appears to be a sweet spot of mesh modelers.

https://cad.onshape.com/documents/ffca40e65fb929c1b8619e1d/w/6ad98b01057950bbc27b688f/e/ffea3638429a93dbcdee7548?renderMode=0&uiState=695a6d67a9c38288fe91b1c9

jason_ryan337

Hi there. I wish to make the column ornate which i think will be very complicated working on a curved surfaces in all 3 dimensions. I was hoping to make the part flat like I show in the image and then bend it afterward. The wrap command is awesome but only works on a cylinder. The work around to use wrap + move face + thicken for a sphere only seems reasonable for less complex features.

MDesign

possible alternative? use split face and then move face. just tossing ideas.

jason_ryan337

https://forum.onshape.com/discussion/comment/125135#Comment_125135

Sorry if my posts seem out of order, there is such a lag in getting my posts approved. I don't understand why this forum requires mod approval of every post, it is very frustrating.

I really appreciate your taking the time to show a new example of making a simple column, it is very helpful. Eventually I would like to add flutes and inlaid beads so I will need to figure out how to do this, but maybe it won't be as bad as it seems.

EvanReese

I'd use the heck outta this feature if it existed! Maybe one day. For now it's modeling it that way or doing it elsewhere (Rhino, Plasticity etc) and importing.

Derek_Van_Allen_BD

Tween surfaces first, @EvanReese. I'm walking the long arduous road towards generalized freeform shape deformation one utility at a time.

EvanReese

https://forum.onshape.com/discussion/comment/125190#Comment_125190

Woo seems like a hard road, but I will be grateful! Feels to me like we need the devs to expose some more Parasolid functionality and it'll basically make itself after that.

Derek_Van_Allen_BD

https://forum.onshape.com/discussion/comment/125192#Comment_125192

I'm actually curious how Plasticity has implemented it because I was combining through the Parasolid documents to try to find the FFD sauce and couldn't find the smoking gun of a utility that's being used.

jason_ryan337

https://forum.onshape.com/discussion/comment/125187#Comment_125187

Hi Evan, very cool that you commented as my hope for bending the columns is part of an effort to make a 3d printed bowl that has the exodus story blended onto the side of the bowl using your awesome new displacement map feature script :-)! In this version of the bowl, I used the image to generate the columns as well as the top and bottom rim features. After printing the images turned out pretty good given the resolution reduction to make the displacement map tolerable. However I felt like the rim features and columns could be much more crisp if I modeled them and would also remove some load from the displacement map.

I am still trying to figure out the best way to implement the displacement map as it didn't want to work with replace face and it was a struggle to figure out a way to make the new surface into a solid. Making it into something I can make an ornate rim feature will be the next issue to work through :-).

This is what I hacked together:

https://cad.onshape.com/documents/86202c50e42847587ee33ffd/w/cc0a2b38dd041a0c369d4ae0/e/5d1d576a3b3a058ef7b04761

EvanReese

Ah, i see. I do think that modeling the columns will be a better result. I'd sweep the main column part (or loft if taper is needed), then model the corbels flat and transform them into position at the ends. Then you could even do a different image per square if you wanted.

Derek_Van_Allen_BD

@EvanReese on the other hand, who needs Parasolid utilities when we can just borrow from my very good friends Sederberg & Parry?

WIP obviously.

EvanReese

https://forum.onshape.com/discussion/comment/125228#Comment_125228

@Derek_Van_Allen_BD 🤯 unbelievable! I strongly recommend taking a look at the functions of each of Rhino's deformation tools for inspo.

Derek_Van_Allen_BD

Ah to be a developer that can make tools that run without a feature tree, utterly unconcerned with build time. I'll definitely be stealing some inspiration from the Rhino UI for the final iteration of these tools but for now I needed direct control over all of my lattice points to prove some functionality. I think my next step is to poke at that Flex / Taper custom feature that's been floating around for awhile and rip out the surfacing core and replace it with proper FFD utils.

S1mon

https://forum.onshape.com/discussion/comment/125228#Comment_125228

I had to follow your breadcrumbs.

https://people.eecs.berkeley.edu/~sequin/CS285/PAPERS/Sederberg_Parry.pdf

And I asked ChatGPT deep research for more context:

https://chatgpt.com/share/695d46ea-b370-8010-b731-ac1344c180cb

Derek_Van_Allen_BD

Here are a few more foundational breadcrumbs to look at.

EvanReese

https://forum.onshape.com/discussion/comment/125230#Comment_125230

I do wonder how extreme you could make the caching to make it more plausible. What's the least amount of work the feature could do if it has data cached somewhere?

Derek_Van_Allen_BD

@EvanReese I had a demo case with 45000 calls to a factorial function at one point and thought about yoinking your displacement map code and plugging it in to shove the Bernstein polynomial calculations into it. Will likely be implemented in the final versions of this feature but it's more important to work on things like surface stitching or knot insertion first before we go for performance boosts.

EvanReese

https://forum.onshape.com/discussion/comment/125252#Comment_125252

One thought I've had for easier caching that doesn't require much forethought is to literally cache the whole definition. You'd just have a hidden isAnything() param and shove the whole definition in there and return it. There might be some kind of extra step to prevent recursion or something.

Derek_Van_Allen_BD

https://forum.onshape.com/discussion/comment/125253#Comment_125253

Like a definition > old definition type thing? Could probably work.

EvanReese

Could be great reasons not to, but I just mean something like.

definition.cacheDef = undefined;

definition.cacheDef = definition;

You'd still want to do some other calcs in editing logic and add them too and add them, but the cache could just be one big map o stuff. Thinking more on it now there may not be all that much utility in storing the whole definition, but maybe no big downside either.

Derek_Van_Allen_BD

@EvanReese Wheeeeeeeeeee

EvanReese

@Derek_Van_Allen_BD That's so cool I'm making involuntary disgusted faces! I can't believe how performant it is too! Wow wow wow

Derek_Van_Allen_BD

@EvanReese it gets cooler