I’m designing a baffle for a speaker cabinet, and none of the things I know how to do are working. Photo is “close” to what I want, but full of issues. The only thing I can tell for sure is there’s gotta be a better way!
I have tried several strategies, but either they turn out wrong, or they fail at the last step due to a conflicts created in the previous steps.
The goal is to create a surface that is tangent to the corner fillet (1" on all corners) and tangent to the radius on the central “8” feature. The “8” feature is raised 3/4". I want the corner fillet to be consistent around the entire speaker cabinet for continuity. But this is what’s making this difficult!
The picture is the result of a fairly dumb and labor intensive approach, but it is the best I can come up with.
It isn’t quite right, and it is full of problems, but it was good enough to let me machine it. I fixed the result with bondo, but it still isn’t quite right.
How would you do it? What commands, and what sequence?
are you after - something similar to this ?
the surface is nearly developable (curved in one direction only) - I used a (non-public) script from another project to do it - no finetuning… not super nice as the small radius is targeting towards the corner … looks a bit like sheet metal work. (the script is from this context)
… at least the surfaces shows some limitations the geometry has.
It looks a lot cleaner than what I came up with! The bump-roll is an interesting solution. It’s a different shape, but it is a valid solution.
However, I don’t know anything about writing scripts. I’m just scratching away with the basic commands.
The look I was going for was more along the lines of the speaker drivers pushing their way out of the cabinet from the inside.
The obvious solution would be to use something like the Drape command, but in it’s current form it seems useless to me. But it would be great if it behaved more like a sheet of rubber stretched over the surface. If it followed the existing surface, and create a taught surface between features that create high points.
more like a rubber, pressed im from below …
less mathematic-like.
a ruled surface, but not developable…
still the influence from the corner into the surface is visible…
That looks like what I was trying to do. I can live with that issue on the corner.
Can you explain how you got to this? I can see that you constructed the initial shape differently. I’m suing old fashioned fillets as though I was using AutoCAD, and apparently I’m hitting a wall.
the ruled surfaces:
again with a non-public script. sorry.
but feel free to use above data.
the corner
I tried to make it more flat / less pointy / less sharp to give more room for the surface to flow around it.
the initial surface was a _extrudeCrvAlongCrv , then some / little CV(ControlPoint)-Editing.
I think you will get nicer (Transition/ruled-Surface-) Results if the Corner is completely G2
production
how is the part produced ? cnc-milled in wood / MDF? - so sandpaper will do the remaining job.
Thanks Tom. (And Pascal!) Yes, this will be CNC machined out of MDF, so some sanding or filling is OK. And I’m only making 2. It is the baffle for a large floor standing speaker.
It looks to me like your script automates the process I was using in my prior attempt. It wasn’t complicated to do, but it was tedious. But unfortunately I don’t know anything about writing scripts, so it’s probably easier to suck it up and do this manually, than to teach myself how to write scripts just so I can make a script that does the job for me.
I was hoping there was an existing tool in Rhino I could use as an alternative, but from your answer it seems this is not the case.
And to Pascal, your surface looked good, but on close inspection it did not match up to with the corner radius. Perhaps there is a way to work around that? I’ve had plenty of situations where I made a shape that looked right, but wasn’t quite right…and then I struggled with it for a long time until I gave up and re-did everything.
Sep 5, 2022
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Update: I am revisiting this design. I built one like I drew above, but I was not 100% happy. So I took another stab at it. I used the same technique as before, but this time I was more careful to understand the relationships between the geometry.
My main complaint was the transition at the bottom. Before it had a radius down to a flat surface, and the way the light reflecs on it accentuates this curve in a way that I don’t like. It ends up looking like it has a “chin”.
I had some issues with this bottom section. To make it transition smoothly without defects, I extended the bottom end of the surface by adding a semi-circle, and I made the radius follow the semi-circle. This made the radius continuos around the entire part. Doing this eliminated any unwanted creases/ defects.
