hscmom wrote: ↑
January 4th, 2021, 5:32 am
Hi All, After being silent (but lurking...) for a few years, I'm writing to ask for help in supervising WICI at both Regional (mini format) and State (I hope satellite, but could be mini). I've played around in both FreeCAD and OnShape and have discovered that I do not have a CAD mind. I have wasted dozens of hours going down bunny trails and hitting dead ends. I understand the event rules and what I need to accomplish and I am comfortable with creating the rubric for grading as I have supervised WIDI at tournaments for a few years after retiring from active team coaching. Is there ANYONE here that can help talk me through all I need to know to create/import shapes and move them around??? Probably OnShape, but FreeCAD is an option. THANKS.
The primary workflow for both FreeCAD and Onshape is drawing a sketch, then modifying it to produce a solid of some sort. I have more experience in Onshape, so ig I can focus on that. For most basic shapes, you just need to sketch a shape on a plane and extrude it (it's called pad in FreeCAD). For example, if you need to make a rectangular prism, you can choose a plane to sketch in, draw a rectangle, confirm the sketch, then extrude it to the desired height. If you want specific dimensions, draw the element arbitrarily and then use the dimension tool where you can edit the parameters. You can also create construction lines to aid you in drawing the sketch. For example, if you need two circles with their centers at a specific distance apart, you can draw the first circle, then create a construction line at the right distance, then draw the second circle. There are also certain constraints that can help, like making something parallel or perpendicular to something else within the sketch.
Since you just need to provide the individual components, you probably don't have to get too fancy with splines or lofts or anything like that. You can also extrude negatively, for example, drawing on the face of an existing object then subtract a certain amount.
You can have multiple components in the same file in Onshape by using the part studios, so you can design one piece in Part Studio 1, then another in Part Studio 2, etc. Then, you can use an assembly to have all the pieces in the same space for the competitors to rearrange as they need to.
I think you can import most kinds of CAD files to Onshape and it will process it for you, and you just need to add it to the assembly. You can download quite a few objects online from things like grabcad and thingiverse.
In assemblies, the objects are connected by mate connections, which come in a variety of types with different constraints and degrees of freedom. You probably only need to use the fastened mates. You can place the connectors at certain points on each part and then "mate" two pieces by selecting which kind of mate you want to use. It might be helpful to rotate the pieces into the intended orientation before mating them so it will do what you want it to do.
This is a bit hard to explain without pictures, but Onshape has a series of tutorials that they produced. Under the question mark icon next to your profile picture, you can click on the learning center and there are a bunch of videos there.
Hope this helps!