3D bent washer shape

[kerpez]

I'm working on a chair design and need to creat a bent washer shape,( as if you were to put a washer in a vise then bend over the portion sticking out). I thought about subtracting solids from a column but the edges would not be correct. Any thoughts?

[CipesDesign]

OK, here's a thought (which might or might not work!). Start by making a 2d washer in plan view by clipping the surface of a circle with a smaller circle. It would look sort of like a donut. Then extrude the washer to it's actual thickness. Now switch to a front (or side) view and create another extrusion out of a very skinny rectangle such that it will intersect the washer at the point where you want the bend to be. Make sure to verify that the shapes overlap each other in plan view (or move the second shape so that it does), then select both shapes and go to the menu item MODEL>SUBTRACT SOLIDS. Choose the washer as the shape FROM which to subtract. Now you have two pieces of a washer. Select the one that bends and rotate it to whatever angle it needs to be, then drag it over to the un-bent portion. Select both pieces and got to MODEL>ADD SOLIDS. I think you will have what you need although a bit of trial and error may be required for fine tuning.

If it works, well cool! If not, well sorry for the long message...

Peter Cipes

Residential Designer

Ashland, Oregon

[kerpez]

thanx for the reply, I tried that early on to no avail, the parts won't intersect with correct geometry-Kerpez

[bclydeb]

Kerpez,

quote:

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Originally posted by kerpez:

I'm working on a chair design and need to creat a bent washer shape,( as if you were to put a washer in a vise then bend over the portion sticking out). I thought about subtracting solids from a column but the edges would not be correct. Any thoughts?

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Try making a bent rectangular plate. Use double line ploygon tool and draw say an 1/8" elbow shaped item in say front projection view. Then extrude it. Using the 3D modeling tools draw a short cylinder taller than your bent plate and the correct diameter for the hole. Use the center 3D alignment tools to line them up. Use the cylinder to punch (subtract) the hole in the washer. Finally create a cylinder taller than the bent shape at the washer outside diameter and center over the hole. Finally do a 3D subtract where the cylinder subtracts the outside stuff. hopefully you will get something close to what you want. Delete the cylinder punches/cutters and ? what is left should be the bent washer.

I haven't tried this out but it should work.

Don't you just love us armchair helpers who don't experiment before we advise.

[propstuff]

If what you want is a bent over washer, why don't you just make the washer with Clip Surface, Extrude it to thickness, Split it with the Split tool to make 2 halves, then rotate one piece to the angle required, butt the 2 pieces together and align them with the Align tool and join them with Add Solids.

Perhaps you want Radii on the "bend"?

If so try the Fillet tool, -although I've personally found it to be so unreliable as to be useless.

cheers

N.

[tom kyler_dup1]

kerpez, here's what you need to do. Basically, you're going to create a thin surface...and then give it some thickness using the shell tool. First, you need to create a half a washer using nurbs. I did it by drawing two nurbs arc ( concentric with each other of course) and then using the skin tool to make them into a nurbs surface resembling half a washer. You then duplicate (or mirror) that half of the washer. Then go to a side view and using the 2D rotate, you can rotate the new half of the washer (essentially bending it) Then once you've got the angle you like, select both surfaces and go to model > add solids. At this point you can select the fillet tool and fillet the "bend" lines (one on each side of the center hole) This will then give you a bent washer surface, but with no thickness. This is where it gets tricky though. In your object info palette, the status of the object will be "fillet". To reliably add thickness to your washer (or seat) I select the object and then do a 'model'>'convert to nurbs' and then ungroup the whole thing. I then have four nurbs surfaces. I then select the shell tool and set the thickness to a small value (having trouble with larger values) and then thicken up each surface one at a time. You can then select the four "thickened" pieces and 'model'>'add solids' to create the finished washer. It looks like you just put that washer in a vise...and hammered it over. If you decide you need a thicker washer, then you can convert the whole solid to nurbs surfaces, ungroup, and then thicken up the back surfaces again, but then things become more tricky....but doable, I've created a really thick washer with the inside and outside edges radiused to soften up the look a bit. If you need to go that far, just ask. Good luck

[ 06-10-2004, 01:25 PM: Message edited by: tom kyler ]