Modeling Challenge: Handles

The next surfacing challenge is a handle. If you want to participate, just make some sort of a handle, and send it to my email address (matt at dezignstuff dot com). This is a non-descript handle, the main traits I’d like you to aim for are:

• the rounded end, or really anything but a flat end.
• the finger grips
• experiment with freeform
• experiment with deform (actually, this is a nice way to make grips)
• remember you can loft to a point and assign tangency to the point to round off the end of a loft
• if you use some software other than SolidWorks, just tell us how you made it (screen shots of reference data or in-progress pictures would be great).

My part is in SW09 format, but you can use whatever you like. The part I made was a 3 minute part with only 2 sketches, not very carefully done, so I expect yours to be better than mine.

================================================

Entry #1 is from Charles Culp in the form of images. Charles designs joysticks in the course of his day job at Essex Industries. These images are the property of Essex Industries, used here by permission. Here is what Charles has to say about these designs:

 

Here are three examples. The first two were designed in Solidworks. The third was designed in CATIA (by our customer), then imported, remodeled and modified in SolidWorks. These are all for commercial planes.

The first grip was modeled in SW, then 3D printed, then modified with tools (knives, sandpaper, etc), then re-scanned. This process was done twice, to optimize the shape for ergonomics. Each time the model was placed “on top” of the scanned model, and parameters were changed to match the scanned shape. Changes of .050″ can make a huge difference in how it feels.

Note that the second one has a “simulated trigger”. There is just a place for the index finger to grip, and separate from the other fingers. This creates one single scallop, which is beneficial when you have a requirement to fit a large variety of hand sizes. Adding scallops for every finger can be uncomfortable for really large or small hands.

 

Entry #2 is from Itai Lewin, and employs some interesting techniques. The first Extrude is to create a reference surface, and it is mirrored to allow opposite sides to be lofted together. Like the spoon earlier, Itai used a left, a right and a center loft profile. This is common, and the technique can be used for many different symmetrical shapes. Both sides were lofted. I assume the front and the back were lofted separately to minimize the influence of the wavy grip sketch.

Then the body was flexed to give it an interesting curvature (the Move/Copy feature was added by me so you could see the original and flexed bodies at the same time).

Nice job! Very interesting model.

================================================

Entry #3 is from Lin Shao Dun. If you aren’t familiar with Lin, he is the one who walks away with the SolidWorks Beta contest every year for the last several years.

In this model, he simply revolves a shape, then uses Deform to add shape to it. Beautiful. Nicely done. Deform is considered a “direct editing tool” because it can edit the shape of both native and imported geometry. To use the Deform, just draw a sketch that represents the shape you want an existing edge to have, then tell Deform to deform from this edge to that sketch. I think “curve to curve” deformation is the most useful option in the Deform tool. Nice example, and a very simple tree.

================================================

Entry #4 is also from Lin Shao Dun. This shows the subtle difference between something that works and something that doesn’t. If you have a close look at this part, you can see that the sides of the handle are lumpy. Freeform does something called “teetertottering” (ok, I’m the only one who calls it that), but when you move one point down, Freeform moves another point on the opposite side of a fixed point up. Just like a teetertotter. Again, Freeform is another direct edit tool because it enables you to change the shape of existing geometry, native or imported. Notice that he caps off the rounded end with a Fill surface.

Another nice example. I commend Lin for sending in attempts that don’t necessarily represent perfection. We all learn more from failures than from successes.

================================================

Entry #5 is again from Lin Shao Dun. In this one, Lin uses a loft instead of a boundary, and comes up with very similar results.

One of the main differences between boundary and loft is that loft can make a closed loop where boundary can’t. Boundary can only make a closed loop if you have a closed loop as a direction 2 curve. In my example, I had to mirror the boundary. Lin doesn’t have to mirror his loft, although he did in this case.

================================================

Entry #6 is from Lin Shao Dun. This submission uses a sweep. A sweep can potentially get you into trouble on a part like this, but Lin avoids the trouble nicely. The path in this case is the sketch on the side of the handle. When you use a curved path, you need to at least consider the “keep normal constant” option. In this case, Lin used that option, and it keeps the profile facing in the same direction instead of following the path around the curve.

Another potential problem with a sweep is that you get lulled into using a circle or an ellipse for the profile. An ellipse as profile would either fail or allow the finger indentations to cause undulations on the far side of the handle. Lin got around this by using a spline. Definitely my recommendation. He even got the spline handle relations correct so that the mirrored sweep shows tangent to the original surface. Again, very nicely done.

The last problem you can run into with a sweep that ends at a point is that the point can be messy. That in fact happens in this case. Lin dealt with it correctly, and cut it off with a trim, then patched it with a fill, using an existing curve as a constraint curve. The only problem here is that the mirrored fill does not show as tangent to the original (remember to use the “View, Display, Tangent Edges As Phantom” setting to tell immediately if surfaces that meet at an edge are tangent or not). To get around this, he might have created the Fill after the mirror, and used a different constraint curve.

================================================

Entry #7 is from Dan C. Dan made a loft and his finger grips were more precisely planned than mine. He also capped off the end of the handle with a loft that used tangency weighting to get the rounded shape. Tangency weighting is often overlooked in splines and lofts.

Nicely done, and thanks for the submission!

================================================

Entry #8 is from Chris Huntley. This is one of the techniques I was hoping to see. Chris started off with a boundary for the basic shape, then split out a section and used Deform to reshape the finger grips. This avoids the finger grips from influencing the rest of the handle shape.

Also, nice shape on the end of the handle created with a boundary to a point from an edge. Very cool model.

================================================

Entry #9 is also from Chris Huntley. This one uses Freeform instead of Deform.

This is what Chris had to say when commenting about the differences between the two features:

two variants of a rather unexciting handle attached (SW2009).  The first, after a bit of fiddling, uses a deform-to-curve to create the ‘finger’ grips.  The second uses a freeform feature.  My modelling is a bit cut-and-shut.

I’ve not really used these tools before but both seem to be relatively easy methods of creating the grip form, if not offering the finest control – freeform seems to like adding wrinkles and with deform the result seems to be at the mercy of the controls.  I probably need more practice tho.

You’re definitely at the mercy of the tools. “Cut-and-shut” must be the Brittish equivalent of “hack and whack” or something along those lines. This is just an online modeling challenge. No one is going to criticize you for not getting outrageously detailed here. Showing cool techniques is what it’s all about.

Nice model, and thanks for showing your stuff!

================================================

Entry #9 is from Michael McCune. Michael just sent images, no model, but you can clearly see what he did from the images. The finger grip sketch uses dimensionable arcs, and allows for a more controlled shape. Click on the images for a larger version. Notice the straight section at the base of the grip, still created with the loft or boundary.

This is a nicely done model with great shape and control. Black is a very difficult color to render properly. Michael achieves it here with the use of a bit of texture to reflect the light smoothly.

================================================

Entry #10 is again from Dan C. This time he split up the sketch along the side to control the angle of the finger grips somewhat. This is a nice idea and a good way to control the model. I’d like to point out, though, that there is an easier way to do this, although it may not offer as precise control. Sketch2 could have been one continuous shape if the loft had made use of connectors to direct the flow of the surface from the grips. Where Dan’s first model was fairly straight, notice this one slants inward. This can be controlled by loft connectors.

================================================

Entry #11 is from Costi. This model uses the Freeform feature twice. Once was for the finger grip and a second time for the gentle arc on top of the grip. The two faces are separated by the split line. Nicely done. Notice, though that with the Freeform feature, you are less in control of the shape than you might hope. You still get that very characteristic spline-like shape. This is something I am just noticing now, comparing the various models made from different methods.

================================================

Entry #12 is from R. Paul Waddington, the AutoCAD reseller from Australia. The model comes in the form of images only, no solid part file. This is what RPW has to say about modeling the handle:

Using AutoCAD, tho’ this time 2009, have chosen to model a saucepan handle.

Image 01 shows the five profiles used, the two end ones being lofted along the upper an lower splines and the other profile used to form the concave end. Did exaggerate the lower spline, somewhat, to force the ‘finger’ locations to be both convex and concave closer to the pan end of the handle.

The embellishments, button (with molded insert), hanging ring, ferrule (with dovetail joint) and hole/counterbore for screw and button, were done just to make it a complete exercise.

Once I started your handle challenge I realized it might be a good training exercise for those I teach AutoCAD modelling too and having completed it I will use it for that purpose.

Additionally I would like to dedicate this model to an Autodesk employee, a Mr. Andrew Anagnost.  Andrew has always had a great vision for Autodesk’s mechanical modelling so I am sure he will be ‘tickled pink’ to see this done in AutoCAD.

I look forward to see what other have done and thanks again Matt for setting another challenge.

================================================

Entry #13 is from James Canney. This model has several discussion points. It is a little more complex than the other models.

The shape starts off with a loft using 3 U shaped splines as profiles, and 2 U shaped splines as guides. Download the file and check it out. The only criticism I would offer here is that the loft cannot control curvature across the guide curves, so on this part you get a bit more of a ridge along the plane of symmetry than you might want. For this reason, I would have used a Boundary surface, and set the 2 guides as Direction 2 curves and set them normal to profile. This would have avoided the appearance of a ridge.

From there James trimmed the loft to shape and mirrored it. Notice that he uses a mirror here and then another mirror at the bottom of the tree. This is a trap that is easy to fall into on complex parts. Don’t put yourself in a situation where you wind up redoing the same work over again, especially in a history based system where it remembers what you do. In this case, I would leave out the first mirror, and model the thing all the way to the bottom in half.

Next is a Freeform feature to shape the grip. Nicely done.

The inset for the grip area is the most interesting feature here, to me. The way he achieved this was to offset the surface, then extrude a surface at the boundary of the inset, and perform a trim cutting away the grip part of the larger surface and the outside of the smaller surface, leaving a small step for the extruded surface. Don’t sell Trim short. It is sometimes a difficult feature to deal with, especially when more than 2 surfaces are involved and when you can’t see either the section to keep or section to remove. In this case, you have to look inside the open end of the handle to be able to select the right pieces.

James used a Boundary to cap off the end of the handle. I would use a Fill simply because of the degeneracy, but Boundary seems to work.

Models that are more involved tend to open themselves up to more commentary. This is a well done model, with a very nice finished shape. Thanks for this late entry!

================================================

Entry #14 comes from Mark Reader. I’m always interested in what other CAD packages can do, especially the affordable ones, like Moment Of Inspiration (MoI).  Mark used 2 sweep features to create this, and it comes into SolidWorks beautifully. MoI uses the Rhino file type (*.3dm). I particularly like the way the bulged section and the step on the top half blend into a smooth face on the bottom half.