Measuring on non-planer surfaces

Hi,

I have a non planar surface -- in this case a portion of a large
cylinder. I need to measure how far apart holes are on the outer
surface -- so they can be drilled when the cylinder is flat.

Any bright ideas ??

TIA,

 

presumably you know the radius-use the axis of the cylinder to measure angle
between features and an edge and work out the ratio to the
circumference-i.e. 36deg= 1/10 2piR- use the measure tool for offset
parallel to the axis

 

Gavin,

Model the cylinder as sheet metal, and flatten it

Regards

Mark

 

You could also look at it from the end (normal to the plane generated by the
2 holes) and create a sketch that consists of an arc on the surface. This
would start and end at the axis of each of the holes. Then put a ref
dimension on the arc length.

WT

 

... I need to measure how far apart holes are on the outer

Gavin,
In the model, create a sketch on a planar surface that shows the holes
in profile or select a plane that is representative of this view. Use the
edge (convert) of the outside cylinder, place two construction lines at the
hole centers, trim the arc and then input an arc dimension. This is done by
selecting both arc end points and then the arc itself. The selections can be
made in any order.
Eddie