3D Sketching??

frank_otuo_mensah

Hi All

I wanted to know if there is a tool in Onshape that allows you to do 3D Sketching, such as in Solidworks you can use the 3D Sketch tool to draw lines in the Z direction/axis ??

alnis

There isn't a 3D sketch tool in Onshape like there is in Solidworks. However, there is usually a way to make the intended model as quickly as with a 3D sketch using 2D sketches. Keep in mind that the edges of parts (solids) and surfaces are valid inputs in features where you need an edge input, such as in the beams feature for creating frames. What are you working on modeling?

frank_otuo_mensah

Many thanks for your response.

I am just following a tutorial to model a Caterpillar.. I know you can use the Sweep feature to follow a curve but the problem I am facing is which plane to draw the curve on?

Kind Regards.

frank_otuo_mensah

alnis

The way I would approach this would be by defining the sketches on mate connectors on-the-fly like so:
https://cad.onshape.com/documents/38b5d742597990ccf1222c98/w/749cbebc9217cb71daddcb6a/e/33d938b281b5018bd737fcfa

I've found 3D sketches to be pretty cantankerous and prone to rapid unscheduled disassembly in Autodesk Inventor (though that might just be me not having spent enough time learning their ins and outs), so I generally prefer working with 2D-sketch-based workflows. In Onshape's case, it's pretty easy to make mate connectors to define sketch planes on-the-fly, so I feel like the tradeoff of slightly lower speed is worth the more robust end result that rebuilds more consistently.

Hope this helped!

frank_otuo_mensah

Hey,
That really helps!! Many thanks.
I love this community!!

Cheers.

bruce_williams

@alnis_smidchens
that is a revelation for me.  Thanks for the example of '3D sketching' Onshape style!  I like and will use several of the methods you have here.

alnis

@frank_otuo_mensah @bruce_williams Happy to help! It's always fun to share modeling strategies.

Ste_Wilson

I think I just offset planes for this:
https://cad.onshape.com/documents/a964344bd82715630af3dde8/w/bdaf2e49ef4c2833b4178389/e/cf1c0f3cff589bbc93582dcc

frank_otuo_mensah

@alnis_smidchens  I have improved the Part drawing thanks to your strategy

https://cad.onshape.com/documents/7dc2d97f9d87a737d62f3534/w/9efae14dea7e794d00b0526b/e/61305029cba9d993ef98f8b2

alnis

@frank_otuo_mensah sorry I haven't gotten back to your question yet! I'll try to answer it in a video format so that it's easier to follow. I can't access that document. Do you have link sharing enabled?

frank_otuo_mensah

@alnis_smidchens

https://cad.onshape.com/documents/7dc2d97f9d87a737d62f3534/w/9efae14dea7e794d00b0526b/e/61305029cba9d993ef98f8b2

Mike_Beck

No. 2D sketches to create complex splines such as a series of tubes running from an inlet manifold to manifolds mounted in different locations that require the same lengths is 20th century. Solidworks 3D sketches cut the design time by at least 50%. I am currently working a project with this specific application. I have to model it in SW, export it to STEP then import it into Onshape to get the definition required for design intent. It becomes a dumb model in Onshape and if it changes, I have to repeat the workflow.
Onshape needs to come up with a 3D sketch option so that we can all walk away from the other CAD freely.

R_Otero

https://forum.onshape.com/discussion/comment/72298#Comment_72298

I agree that there are some design intents that just can't be achieved easily or at all without 3d sketching, as in your case. My preferred workflow for frame work is to make a solid body, then include the edges in a 3d sketch and delete the solid body to obtain my profile paths. In Onshape, I can use the edges of solid bodies themselves as paths, which is quicker than making 3d sketch. However, more freeform paths are not as easily replicated and can easily break. In my freeform example, it took 4 sketches and 4 planes to replicate what one 3d sketch could have done. all because my sketch path requires fillets to make pipe bends. And if you adjust either of the 2 base sketches too far, it breaks the last sketch or frame feature because the tangency constraints flip inexplicably.

examples

R_Otero

UPDATE: It appears that the 3d lines custom feature is a lot more stable than using the 3 point planes and additional sketches. I used the verts from the base sketches as inputs and specified the radius. It doesn't break the frame when modifying the base sketches. While it still requires an input, it is much quicker than the alternative.