Autocad20006-Extrusions

[Hitch]

Anyone about this aft thats up on Autocad?

I'm having some trouble, i want to draw a piece of tube basically...

I start with a 'Donut' do the dims, then use the extrude command.
When its done, it caps off the ends.

Im not very good on it tbh, never been shown, just self taught.

 

[snowcat]

Autocad sometimes does this when you extrude to the same length as the shape, its because its counting line thickness, if you extrude longer than the shape, it will cut the centre out hollow.......

 

[Hitch]

Good man

Ill try trhat in a min

 

[Hitch]

Err, if i strat off with a 2d donut, not a circle drawn inside a circle, it only asks for one extrusion length...

If i do a circle inside a circle, extrude both, the inner being longer than the outer, then use the 'subtract' tool, i can do it.

I thought the donut would be the best way to do it though?
Or is there a better way, how i do it at the monent seems quite long winded.

 

[snowcat]

actually hitch, ignore the donut, the bullion commands play silly ******s when working off templates, just tried it.... quick way, draw a circle, extrude it, then subtract the centre away, save you hours........

I always draw in lines then use the extrude to turn it to a 3D solid then subtract or union it to other parts, quite a few commands don't like 3D as solids and work better in wire frame......

 

[snowcat]

IMHO best to avoid the templates altogether, If you type from the command line the method only takes seconds.....

 

[Archie]

I'm afraid I don't use AutoCAD so I'm not a vast amount of help but I am curious! It sounds like you're extruding the two circles individually and subtracting one from the other. Is it not possible, once you've drawn the two circles, to create a surface or section (as the software I use is pleased to call it) from the two circles and extrude that?

 

[snowcat]

no auto cad recognizes a solid but needs a double extrusion to subtract it over wise it thinks the line is 2D, well as far as I know but theres a thousand ways of skinning a cat.....

 

[Archie]

no auto cad recognizes a solid but needs a double extrusion to subtract it over wise it thinks the line is 2D, well as far as I know but theres a thousand ways of skinning a cat.....

Very true!

 

[Paul.]

Extrude your 2 circles, then use subtract from the modify/ solids editing menu, (or type subtract at the command line), select the solid you want to subtract from. (outer cylinder), press enter, then select the solid you want to subtract (inner cylinder) press enter, render it, job done

 

[Hitch]

Cheers people. Thats how i ended up doing it Paul, though for a moment there may have been a simpler way

Half my trouble is i will work at it for a bit, then get bored, not use it for months and months, then forget everything id picked up

 

[snowcat]

Hitch found a quicker way, draw your donut, then from the modify menu, pick 3D Operations, from the sub menu "Convert to surface" click on your donut then extrude.....Its because you need to convert the template to a 3D shape before CAD will recognize it as one joined object....... this appears the way with all the shape templates....

 

[Hitch]

I dont appear to have that option in 3D Ops, i have arry, mirror or rotate...
Are you using 2006 also Snowy?
I think i will have another play tommorow, getting a it late for it now

 

[snowcat]

I'm running 2007, but I don't think there new on the 07 version, the command line script is "CONVTOSURFACE", if it wont play ball the 06 version cant have it......let us know how you go when you've had a play, if thats not an option you might be able to do a pedit to convert the shape, or thicken it.....

 

[Paul.]

2006 doesn't have it, pedit can only be used on polylines, 2007 has a few new useful features for solid modeling,

 

[reno]

Looks like I may be a bit late for this but...

When you draw a circle or donut for that matter you are basically creating a flat disc on the page; that's why when you click on it a handle appears on the centre point as well as the quads. By extruding the disc your giving it a thickness. TBH the donut command isn't one a use often so I'm not too familiar with it.

The quickest way to produce a tube is to draw the inner and outer walls separately, extrude and then subtract the inner. As TIGPAUL suggested.

AutoCAD has 2 ways to do 3D, firstly as surfaces where you apply a face to a shape (this is mainly used by architects) and secondly solid modelling which actually creates the shape as a solid.

I hope that helps!

Cheers reno

 

[Hitch]

Ah, cheers lads, ill carry on doing it as i were then