Alignment question

[Jeff]

Hello,
               I have a lens that I have aligned using best fit to cad. I would like to align the lens to the cad using 6 surface points. We are using A1, A2, and A3 to align in X. B1 and B2 to align in Y. C1 to align in Z. I like the way the 6 surface point alignment works because you can set the alignment direction. The problem I have is that I am not probing this part. I would like to take and extract the measured data from the scan data. I do not see a way to do this using the 6 surface point alignment. I do not want to probe this. Is there a way to do this without probing? I tried to use N pairs of center points but A2 is out by over 1mm. It looks like it is aligning B1 and B2 in the X direction and not A1 and A2. Is there a way to set the alignment direction in N pairs of center points? Is there a better alignment method to get the results I am looking for? Thanks!

[Admin]

My first thought is to make use of Reference Points and use those to align it to, and then use the constraints during the alignment to restrict the degrees of freedom.  I'll try to look into this later today.

[Jeff]

I was able to do the alignment by using Reference points. I first did a best fit alignment then defined the reference points. You can set the alignment direction when you are creating them. This seem to work well. Thanks! Jeff

[PW User]

6 surface point alignment was designed to be probed. It's not for your lens.

Reference point is exactly what you should use. I't a very flexible way to do this alignment.

Depending on the curvature of the lens, you may want to use small planes to bind you reference points. One creation method I like is this one:
1- Select standard reference point creation;
2- Method: from feature;
3- Feature type: plane;
4- Set the alignment direction and press the "Create button"
PolyWorks will lead you to a plane creation
5- Set the method to Anchor
6- The Sub-method to "Pick 2 on Surface"
7- Set the radius to something small (this depends on the curvature of the lens, but try the default and see what it looks like)
8- Set the number of sides to 6 or higher
9- Pick a point on the CAD surface

A reference point AND a small round plane gets created. Upon alignment with reference points, the plane will get extracted and have a functionality similar to a "bumper""

[Jeff]

Thanks PW User. I will have to give that a try.