Practical surface modeling tips and tricks - good curves and diagnostics are your friends

[@evanareese]

I’d love to see a deep dive on Face Blend specifically. There are so many inputs and options to wrap my brain around!

[@gregbrown-onshape7555]

Yes I can definitely look at doing some deep dives down the Face blend rabbit hole... There's a lot to unpack!

[@olmosbananas]

this is pretty awesome. surfaces are still something i never use since im still relatively new to the game, but looks like a great tool to have.

[@gregbrown-onshape7555]

That's great! You know a lot of people don't realize the depth of the surfacing tools we offer. They are so well integrated into the rest of the Part studio that it's easy to skip over them since they are not sticking out in their own. Once you know though...

[@FTCHub-EpicVault]

Love your content!!

[@designX404]

Hi , Lewis here. Thats a good deep dive video for surfacing. Would you please make a video to differentiate use cases of 3D Fit Spline vs Bridging curves coz both curves seem similar though Bridging curve is more smooth. Thanks

[@gregbrown-onshape7555]

It's a good idea for a focused video and I'll add it to my list. I can describe it pretty quickly though: A 3d fit spline is an interpolated spline of degree 3. In some systems it is called an Edit point spline. Note: when a 3d fit spline consisting of only two points and no adjustments are made to derivatives - it then results in a deg 1 line. For 3 or more points, you'll get a multi-span degree 3... A bridging curve always creates a single span (Bezier) curve of varying degree according to the boundary conditions. For a G3-G3 curve you'll get a degree 7 curve, for G2-G2 you'll get degree 5, etc etc. In terms of use-cases, a 3d fit spline is great for creating cable routes or paths than need to pass through a given set of points. A Bridging curve is for creating high quality profiles, guides, boundaries for (primarily) surfacing features (Boundary surface, Loft etc) where the distribution and number of control points needs to be controlled precisely.

[@Amanda-ut7gx]

your videos are the most helpful out of what I could find so far! extremely underrated :) could you make a video that goes more in depth on how to strategically place curves when modeling objects (e.g. phone case, game console, car hood, etc.) Whenever I try to surface model complex shapes, I often end up with strange, unwanted creases in certain areas. This happens because I'm not sure how to properly set up the curves or which tool to use-whether to go for a boundary surface or a loft. Seeing it visually and understanding the reasoning behind it would help a lot!

[@gregbrown-onshape7555]

A really good comment - thanks for the suggestion. It is pretty hard to generalize completely the approaches. There are some nice guides (especially the Alias Golden Rules -- this one has been duplicated in various systems but the approaches are all equivalent) but it's going to depend on the part you are designing. A toaster, a cell phone, a car will have different challenges. There are nice "patterns" (approaches) you can utilize to tackle specific challenges - the topology you end up creating will make or break the design. I'll think more on this and see what I can come up with.

[@yasokada1]

Zebra stripes UI is now located at the bottom right.

[@gregbrown-onshape7555]

Yes we consolidated the analysis toolset to the lower right - including zebras, but also for example curvature color map, dihedral, and more.

[@m.e.p.r]

Thanks for the tutorial, much appreciated. I have a question: When Zebra stripes are switched on in the second example, it looks like you are only achieving a G1 result i.e. the zebra strips do not flow between the surfaces as I would expect to see. The splines have a G2 constraint, but the surfaces conditions themselves are set to "match tangent"? I come from PTC Creo, wherein you must also select the surface conditions to be G2/Curvature or G3/Curvature acceleration, is this not the case in OnShape? Looking at the Zebra stripes on the second example, I would not be happy with this result, but perhaps I am missing something? Can you shed any light on this aspect of Onshape please?

[@gregbrown-onshape7555]

This video was shot before the Boundary surface feature was able to take G2 boundary conditions. But that has now been addressed. Loft could have been used (it does support G2 continuity on the profiles as well as the guides) Also since this video, the Bridging curve has been enhanced to support G3 (Flow) connectivity, thus producing a degree 7 bezier (single span) if you use G3 at both ends. Thanks for calling this out. Again this channel might have little things like that as it is not intended as a formal training resource - it is me building, testing and demoing. In any case, I'll put it on my list to update this and release video with G2 boundary surfaces, plus some other curve tricks that have been released in recent times.

[@bibliotek42]

I've only been using onshape for a week but am really impressed so far! I've spent about 4 hours trying to recreate your horn but I can't get the loft function to work. Is it possible to see your file so I can see what settings you used? Thanks for sharing your expertise!

[@gregbrown-onshape7555]

Sure, I'll add a link in a moment.... check the description.

[@johnnydfred]

Can these types of line aberrations occur from projecting a new control line from 2 previous lines?

[@gregbrown-onshape7555]

Yes, projecting two clean sketches can certainly result in something that is quite "busy" in terms of the underlying mathematics. The geometry kernel (in our case Parasolid) will determine the projected spline and place the control points and knots accordingly. It is up to the user and/or application to determine if they want to reapproximate, simplify, rebuild it... Depending on the downstream use this may or may not be necessary. In the initial case I showed it was a truly nasty curve, and I'm not certain how it got to be that way! (I don't know the source of the original data) In my case, rebuilding using clean curves was the easiest route.