Creating an average profile down the middle of two profiles?

[chipman]

I have come across this many of times.

The most effective way to rough some slot type profiles is to drive a cutter down the middle.

I come across the need to make geometry to get the middle of two profile that are not the same distance along each other.

Any one have any tricks up their sleeves, besides manually creating line/arcs. 

I at times have a couple of dozen profiles and it can be time consuming and tedious.

 

The attached mcam file has a sample outer finished profile, and I created a center profile offsetting a few times at different values.

 

profile.mcam

[billb]

You might try the MedialAxis C-Hook.

 

I was able to get it to work on your part.  I scaled the geometry up 10x and retrimmed some arc/lines to close gaps in the chain.

[Roger Peterson]

I wish medial would work on two open chains.  The fact that it requires a closed chain means I need to extend chains and then close of the ends.  on simple geometry this isn't always necessary as you can just extend / trim the center line.

[AMCNitro]

simple, use Offset Chain, or just Offset and offset it to the width divided by 2

[chipman]

You might try the MedialAxis C-Hook.

 

I was able to get it to work on your part.  I scaled the geometry up 10x and retrimmed some arc/lines to close gaps in the chain.

 

Interesting, I got part of it to work with the original geometry, when i scaled it up it would not work?

 

No settings to play with on this c hook?

[chipman]

simple, use Offset Chain, or just Offset and offset it to the width divided by

 

The geometry is not equidistant

[gcode]

This takes some effort, but it works

Use the command Point Segment to put an equal number of points on each contour

Draw lines from point to corresponding point  between the two contours

create a midpoint on each line

create a spline defined by the midpoints

 

you now have a spline at the center of the two contours

 

edit

 

I just noticed the file you put up  and this is not a good solution for your problem

[Roger Peterson]

medial works well when it works.  Geometry needs to be very clean and even then can have problems.

 

 

Medial is easy to try, if it doesn't work, just create an "Engrave" toolpath.  Using the Engrave toolpath pretty much always works but you do have the extra step of projecting the geometry flat.

 

 

HTH

[Brian Pallas]

Could you use contour toolpath on one edge of your shape, use the stock to leave to get the tool where you want it, then save the toolpath geometry out of the backplot?

[chipman]

This takes some effort, but it works

Use the command Point Segment to put an equal number of points on each contour

Draw lines from point to corresponding point  between the two contours

create a midpoint on each line

create a spline defined by the midpoints

 

you now have a spline at the center of the two contours

 

edit

 

I just noticed the file you put up  and this is not a good solution for your problem

Hey, this might not work for that profile, but I may very well work for some others ones.

Thanks for the tip!