Rocket 3F free 3D modeller

Something I made for a friend over the weekend. Was quite the measuring/figuring out challenge. My friend bought a rare 2nd hand roof rack on Saturday but when home, realised one of the rubber pads that go between the metal roof rack foot and the curved car roof was missing. So the challenge was to try to measure and design a mirrored version of the existing one.

But where to start? This thing was all curves with hardly any reference points. Dunno if I've pulled off a good match until we can visit my other friend with the 3D printer but my approach was to work outwards from the only good reference point, the funny grippy grill bit.



Figuring out the curves was not something I'm good at. My idea was to try to measure in a reliable/plottable way, any distances out to the inside edges from the rectangle and hope I had enough resulting points to be able to fit a curve to it. The big X was an interesting one. I measured the max internal distance corner to corner and drew two crossing lines which were dimensioned, and I added a cross point that sat where they intersected. This I constrained to always lie on the center vertical line. I then drew 2 more lines from the lower end points to the cross point and, while I didn't/couldn't dimension these, I constrained them to be equal length to one another. After that it was a case of jiggling the lines/angles around until I got the end points roughly where were meant to be.



I used a spline then on one half to get the curved inside. I found I could constrain the top and bottom weight bars (or whatever they are called) to be horizontal which helped make a good join, then mirrored the curved line about the vertical center line.

Honestly don't know how well this thing will fit but worst comes to the worst my friend can just file away any edges that get in the way. Fingers crossed it goes OK. The bottom was a pain too as again, all curves. This last image isn't the final bottom but an earlier version before I fixed the main shape. You can see one end has a thinner lip than the other so it was a case of using a loft to make the cut which is always fun to do.



I have to admit, when my friend asked I said yes as, being able to make random stuff that needs replacing or fixing was one of my aims when I started to learn CAD. This said, I wasn't expecting such a curvey nightmare. Still, I'm glad I did it as I learnt a few new things in the process and any practice is always good. The process of trying to mentally deconstruct how the thing was made is always fun too. Of course, regarding the bottom at least, the designers of the roof rack would have simply drawn a rectangular block and subtracted the car. But since I didn't have a modelled car to subtract, I had to do things the hard way!

Still, all good fun though
Wistrel

 

Thanks! I certainly feel like I'm improving. Watching Brad's (from Fusion360) Thursday nights "How would I make that?/tips and tricks" series every week for a while certainly helped. Aside from the tips, the general thought process about how to go about the design really helped. I still have a lot to learn/practice though. Still figuring out new things.

No not sure when we'll visit my friend. Probably some time in the next week or so.

 

You may find you have a library or local maker space with one.