Hi everyone,
I’m having some challenges designing a natural, flowing UDH dropout in Fusion 360, especially when combining it with a flat-mount brake. Since it’ll be 3D printed, I’m not constrained by geometry limitations. However, using standard parametric designs made it look too rigid and geometric.
I’ve tried mixing parametric modeling with Fusion’s Form tools, but I’m still not satisfied with the result. Additionally, I want the design to be easily adjustable by changing parameters. Right now, if I modify the angle between the stays, I have to manually readjust the Form, which is time-consuming.
Does anyone have tips for designing dropouts that look more elegant and natural while maintaining parametric flexibility, or how I should go about designing dropouts?
Thanks,
(Here is the drive-side dropout, still working on the brake side)
I think if you want this to be parametric, you’ll need to get a bit more granular with exactly what your parameters are defining. The form tools are pretty great, but don’t provide much guidance when the length starts to change, etc…
I’d be building up something like this from a master sketch that’s on the same plane as the dropout hole, and a number of lofts/sweeps. The parameters would mostly be controlling the elements in the master sketch defining lengths and angles, and then sub sketches with diameters of the elements that are on different planes from the master sketch. This would allow me to make parametrically updated derived 3d sketches that would serve as rails/guides for the various sweeps and lofts.
I think you’d then want to get a bit more formulaic, through trial and error to find what looks good, to create breakpoints when the geometry changes enough. It’s a good reason to try to create the geometry in as minimal a way as possible, so that it’s more robust through parameter changes.
Edit: Just looking at your feature list a bit more closely - you definitely want to avoid building the curvature in a part like this through the Fillet tool.
Hi Lars,
I’m not a Fusion user, but as far as I know the basics are the same in Solidworks which I use.
I’ve been making my models more and more parametric with each new project and I learn new tricks and best practices all the time.
The key takeways I have learned is that you need to try to plan your model from the ground up. Try to figure out your constraints and references early on and build on that. You don’t want to attach downstream references to geometry in the model that you may later want to change, as that may cause the model to break.
Sometimes, at least for me, it’s necessary to first build a model to get to the shape that I want. This process usually involves a whole bunch of modeling steps that can be refined away. So once I’m at the stage that I’m happy with the outcome, I completely rebuild the model with a clear view of what I have to do to get to the desired end result, but I can optimise and reduce the steps to get there.
That way I can reduce the steps in the design tree, making for a more robust model that’s also a lot easier to tweak down the line.
Sorry that I don’t have any Fusion-specific tips to give.
This is the perfect case for surface modeling!
Surfacing is a skill in itself, but it looks like you have a good eye for it with the Form tool.
Like framebuilding, the surfacing rabbit hole is deep and never ending.
The two keys I have found for making a surface model parametric and robust are:
Be careful/intentional with what references you constraint to in a model. Ie - constraining to a random surface patch or fillet edge is a recipe for a model to lose reference and ‘blow up’
Setting up clean layout sketches and geometry early in the model that will drive your parameters. I usually make a side view sketch and a top view sketch and then project the two into a 3d curve that will be my guide rails for the surface.
Lars-
I think you will have better luck using lofts to get more organic shapes while still having a robust parametric model.
You might try messing around with configurations. It makes it easy to toggle a whole batch of parameters. For example I have a stem design that has variations for steertube diameter and bar diameter. So that matrix is 2x2 or 4 options.
Hahn Rossman
