How to draw 3d Arc

[comcu]

Hi,

 

I am trying to draw a 3d arc so we can cut the shape out of a flat bit of material and then roll it into the require radius.

 

i know a little 3d but can get me head around this? i thought if i draw a solid shape then draw vertical lines every 200mm i would be able to draw the curve out flat but i can not get the lines or dimensios to snap to where i want. looking at it more closely it seems i have the radius of the arc wrong but i am not sure how this can be as i have snapped to the lowest and heighest points and also to the centre of the arc, or where the arc should be??

 

i am sure it is something simple but i havbent drawn 3d in a couple of years so i am struggling a bit with this.

 

i have attached a drawing so hopefully someone can take a look.

 

cheers,

 

col

STAIRCASE1.dwg

[dumfatnhappy]

Hi,

 

I am trying to draw a 3d arc so we can cut the shape out of a flat bit of material and then roll it into the require radius.

 

i know a little 3d but can get me head around this? i thought if i draw a solid shape then draw vertical lines every 200mm i would be able to draw the curve out flat but i can not get the lines or dimensios to snap to where i want. looking at it more closely it seems i have the radius of the arc wrong but i am not sure how this can be as i have snapped to the lowest and heighest points and also to the centre of the arc, or where the arc should be??

 

i am sure it is something simple but i havbent drawn 3d in a couple of years so i am struggling a bit with this.

 

i have attached a drawing so hopefully someone can take a look.

 

cheers,

 

col

 

maybe this will help you get a good response as I don't think I understand exactly what you are doing. Which arc are you after?

[ReMark]

It almost sounds like a problem we had in drafting class where we were required to produce a pattern or stretchout of a truncated cylinder. When the pattern was finished we had to cut it out and then fold/roll it back into the original shape.

[JD Mather]

Might be easier in something like AutoCAD Inventor where you can model as finished and then have the software generate the flat pattern.

 

Without giving it a close look it might be a Helix that you need to generate the curve. Need the radius and pitch (rise/run) see the tutorials in my signature.

[ReMark]

Maybe I'm just confused but wouldn't the true shape of your arc (flattened) be more elliptical given that it in this case it is an inclined surface?