Solidworks - Trying to use Boundary Surface on broken edge

Hi all, I am trying to build a PS2 controller in Solidworks and ran into some trouble with the handle. I will post on the Solidworks forums but thought I’d try here too.

I made a top surface and a bottom surface and want to use “Boundary surface” to blend between the two, making it curvature continuous to each surface. The problem is that the first surface edge is a closed loop, but I can’t select the bottom surface edge as a single loop (see second screencap), but only as separate (SW said they were disjointed curves). This means that the boundary surface fails because it isn’t treating the bottom edge as a closed loop.

This is probably because of my messy modeling job – in the screencap below you can see that for the bottom surface I made surface A, B, and C separately, and used some extruded surfaces to cut away and then boundary-blend between each gap (with curvature continuity). But it still only selects one edge at a time, rather than the full closed loop. Would I need to make the bottom surface all as one surface initially?

Any help greatly appreciated – thanks!

Does holding control and selecting edges not gather them all? I take it this where you get the disjointed error?

As far as alternatives go, you seem to be on the right track with the idea of eliminating the 3-part body in favor of a single surface entity. Another option might be to extend the surfaces of the bottom group towards the top by a small amount. Then trim them off with a new surface or an extrude to make sure they are all cut by the same line.

right click on the edge you want and select contour selection. This will bring the menu that helps you select disjoint edges and create it into 1 single continuous edge. This should get the preview to generate.

Thanks sprockets and masood for the quick reply!

The right-click select loops is new to me but looks very useful. Unfortunately it gave me this message below, saying that the boundary tool can’t use contours.

When I tried ctrl-clicking each each, it added them up in the feature editor instead of making the single loop.

But … looking at it, maybe I could extend the trimming surfaces from the bottom and trim the top as well, so one open loop on the bottom meets up with one open loop on the top, each as separate boundary blends.

Right-click and “select multiple edges” or something like that.
Althought it can sometimes be trouble to boundary surface between 2 closed loops when the surface doesn’t “start” at the same point (those green and pink dots) and becomes twisted. You should make guide curves for the other direction, and maybe even do 2 separate surfaces for right and left.

If the issue is selecting multiple edges is the main problem, then all you have to do is create a composite curve. This tool is located in the curves tool bar. It allows you to select multiple edges that are in contact and create one selectable item. Simple and easy. As you pointed out, the lower construction may be a little messy, but keep trying. In addition, do not limit yourself to a boundary surface. You could try a filled surface or lofted surface (you can use two composite curves as profiles in a surface loft). In these tools, you can control tangency to the starting/ending profile and any guides.

On a side note, I would advise considering building in halves. Meaning building this in a half of the intent, then mirror at the end.

The composite curve might work but there would be difficulty in making that side of the surface curvature continuous.

If you can get this single boundary surface to work then you should be quite proud of that…my experience with SW is that I’d almost rather build 2-3 surfaces out of lofts or other methods and manage those continuities, vs try to make that single boundary.

Thank you engio, blaster, and slippyfish. This is all really helpful and I will let you know how it progresses.

Some knobbly surfaces to iron out, but the best luck so far! The comp. curve command is very useful. Used that to loft the top and bottom with a couple guide curves (though I would still like to figure out how to use that with boundary surface, the tangency/curvature options were not visible, only “directional vector”).

Thanks all.

Right, because the composite curve is a child of the larger set of edges, but doesn’t have the surface geometry to pull from in order to make the curvature option visible.

I bet if you put your model or problem on a downloadable site you could have a couple other people trying to solve this issue… :wink:

I sent a model back, when selecting your boundary edges right click and select multiple edges. then select the the second using the same tech. One other trick is to ensure both surface you are creating the boundary surface between have a common start point, this can be done by inserting a split line on the surfaces. This method will allow you to have the tangency/curvature option.

With the compost curve selected as a profile, it did not give you an option to select tangency to face? I have used this so many time I can not count. You can also use it as a guide curve and select tangency to face. What version of SW are you using?

Try the filled surface tool as well, as it can be used in similar situations as a loft.

Thanks Blaster, I did just try it again and it worked (Solidworks 2013) – I think I did a CompCurve of a converted entities edge the first, rather than the edge itself, and this gave an error like Slippyfish said.

Chevis was very helpful and his technique made a smoother surface (he used Boundary with secondary direction curves from a previous surface) than I had, where I split it into 3 main surfaces to blend, like 8 total blends! (See first image vs second bumpier image). I have posted the two files on Dropbox if you are curious, but I think I really need to clean everything up now, ideally re-make a lot of the surfaces.

This help has been awesome, thank you all!

My edit of Chevis’s blend

My messier blend attempt

Tip- your transition surface is a derivative of the surfaces you are building it off of. Your top and bottom surface need some tender loving and caressing to get them a little sweeter which will then be reflected in your transition surface.

Good stuff. I learned something here too.

Definitely agree :slight_smile:

@Robbie_roy…here’s everything and anything about curves and surfacing that SW has to offer by Mark Biasotti, the guy who helps Solidworks implement what the software does.

As mentioned before composite curve is only a quick fix and not something that you’d ever want to use in the end as a profile instead of the actual surface edge. You lose 99% of the reason for using the surface’s edge. Also “curves” is SW are shaky at best.

Lastly is all about mastering the “Selection Manager” when it comes to broken edges. The different options within the selection manager makes it that you don’t have to use composite curve.

Thanks cadjunkie – that is a goldmine. Lots to read up on.