Mousing around
I enjoy surface modeling in SolidWorks. It is useful when you build plastic or 3D printed parts. Most consumer product designs require surface modeling for plastic constructions because the manufacturing process offers a high degree of design freedom, and enables parts to be produced cheaply in large quantities.
But skill needs to be practiced. Some time ago I tried to CAD model a speaker using surface modeling techniques, but I found it quite challenging. I’ve taken it as a personal challenge to regularly model consumer products to pick up new modeling techniques and to improve my quality and speed.
To start off, I modeled Logitech G PRO Wireless Gaming Mouse. I chose this product because of its complex curvatures and shape. I downloaded front and side views to load into my model and scaled them around dimensions called in the product specification. I focused on the model exterior aiming to get good quality surfaces. This exercise took 10 hours to model and took 4 different modeling strategies to find an approach that produced the quality I was looking for.
This is what I learned:
· Some rules need to be broken
When modeling for design flexibility and to enable exploration, it is good practice to avoid modeling in radii from a sketch. Instead, fillets are preferred because they are more stable and flexible. They can be added as a feature at the lower levels of the Feature Manager design tree and are easy to change.
I found that because the Wireless Gaming Mouse has a distinct radius on 2 complex curves that feather out into back surfaces, this is one rule you must discard. I tried my best to go around this, but my model gave me an uneven [CC1] radius instead of a fading crisp one. I found I had to go against the fillet rule to get the result I wanted.
· Check early and often
Use check tools as you go to find issues early and reduce the time it takes.
I wasted a lot of time on this model reworking troublesome surfaces but found them after I had a long design tree. I’ve seen videos from CAD Dimension and Go Engineer (Great Resources) reviewing evaluation tools such as curvature combs, zebra, and curvature analysis, but I tend to use them too late in my process.
I also do not check for minimum surface enough. This is useful when you want to do shell functions. If you can use this to detect faulty surfaces earlier, you can make avoid reworks.
· Be smart about your reference planes
Another good surface modeling practice is to derive all your features from existing sketches. This makes your model more stable. But one must be careful in setting essential reference planes to not restrict your editing capabilities later. I made the mistake of not using one reference plane at a curvature in an attempt to reduce the number of planes in my model. Bad idea. By the end, I found I could not modify a vertex to make a cutout work in the shape. In order to fix this, I had to spend a lot of time going back in my Feature Manager design tree to add a new reference plane and sketch. I faked it in the end, which is not ideal, and in most cases, one does not have the luxury to do so. In further projects, this needs to be avoided.
Despite its shortcoming, I consider this model to have good results for rendering because of its smooth transitions between surfaces. You can find the models in GrabCAD here. And the rendering piece can be found on my portfolio website here.
