Pull hair out over a simple part
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Hi guys.
I have joined up in desperation because I am going insane trying to model a very simple part.
I can visualise the part in my head put I can not for the life of me draw it with pen and paper let alone sketchup.
Description of part:A circle 5mm in height,10mm in diameter.
It has a 1mm diameter hole at its center.
Draw a line from the centre to the outside edge of the 10mm circle.
Now the tricky part to explain.......
I want to lower this line to 0mm on 'one side only' creating a smooth spiralish slope around the circle.
Does that make sense?.I would appreciate any help or suggestions you can offer.
Rebo
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First work bigger [say x10] as tiny faces might not form properly - scale it back down to suit later
Think of it another way...
Think of it more like a 'spiral' staircase...
Draw two helix shapes.
One for the outer edge with the outer radius and one for the inner edge with the inner [hole] radius.
Both of them need one rotation [360 degrees], number of segments and the same height [pitch].
There are plugin tools to assist you [JimFoltz's one is probably the best], BUT you couls do it manually for each helix - draw the one 'pitching' line and then use Rotate+Ctrl to radially copy it, then Move that copy up end-to-end, then repeat until the whole thing is completed one turn.Either way... now you have the two helix shapes and you can draw lines between the matching vertices as 'steps'.
These won't auto-face because each 'step' is twisted because the pitches of the inner and outer edges are different - to get the faces add a diagonal so that each 'step' is a triangle, which can then take a face automatically.
Note that you could also just draw the first 'step' edge as a flat 'curve' profiles and use the two helix curves as rails for my ExtrudeEdgesByRails plugin to auto-form the spiraling mesh surface...DaveR recently did a tutorial on making a helical balustrade post, which also applies to your form, albeit repeated several times around an axis when you only want one 'turn' - http://forums.sketchucation.com/viewtopic.php?p=334819#p334819. There are also several other tutorials for making ramps and screw-threads etc that are also very similar in technique and results... e.g. http://forums.sketchucation.com/viewtopic.php?p=302743#p302743 or http://forums.sketchucation.com/viewtopic.php?p=239767#p239767
The screw making plugin might also be of interest http://forums.sketchucation.com/viewtopic.php?p=122571#p122571 -
Tig I could hug you for those links.
I must thank juan974 for the ramp.skp which he posted to this thread http://forums.sketchucation.com/viewtopic.php?p=239767#p239767I have modded his ramp file to get myself the closest I have been to completing this part.
I just need to reduce the center to 1mm diameter now and then I am done with it, any simple way?.
Circle slope.skp -
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the easiest/fastest way to draw this (that i know of) is with the CurviShear plugin by fredo:
http://forums.sketchucation.com/viewtopic.php?t=29230
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