Constructing a High Plane using a Plane

[ChairsWithWheels]

Currently am running PC-DMIS CAD++ 2016.0. I have probed a plane but would like to construct a plane based on the high points; as if it was sitting on a slab of granite. Only thing I can find is things in PC-DMIS 2018, or the High Points function while constructing, which gives me an error. This would help a lot with my alignments and would like to know what methods I could use to get it to work.

[JEFMAN]

I think you can construct a feature set with the plane hits, (PL1.HIT[1..PL1.NUMHITS]), then construct a high point plane on it.

[AndersI]

The old High Point Plane creates a plane from the three highest points of another plane (or set), but doesn't guarantee that all the other hits are on the same side of the constructed plane - this can result in quite some surprises.

You can try a Translated Plane, Maximum Deviation instead, although I'm not certain it really calculates what we expect it to do - I haven't used it since Tangent Plane came in 2017.

But I think the easiest way is to do an alignment on the (least squares) plane and then locate the highest point, create a new plane parallell to the original through the found high point. Desktop code (untested):

- measure plane PLN1
- align primary Z on PLN1
- ASSIGN/HIT_Z=PLN1.HIT[1..PLN1.NUMHITS].Z
- ASSIGN/HIGH_PT=MAXINDEX(HIT_Z)
- construct PLN2 // PLN1, through PLN1.HIT[HIGH_PT]

[ChairsWithWheels]

Thank you for the responses! I'm still slightly confused. Andersl, After aligning to the least squares PLN1, how would I find the high point then create a parallel plane to that. Wouldn't that just create a plane perfectly parallel but as high as the highest point of PLN1?

[AndersI]

Yes, that's exactly what it does. Not *exactly* the same as an "optimized tangent plane", but at least *a* tangent plane.

[JEFMAN]

If you level and origin Z on PLN1, then ASSIGN/V1=MAXINDEX(PLN1.HIT[1..PLN1.NUMHITS].Z).
Create a gneneric point with PLN1.HIT[V1].XYZ and then create a plane // to PLN1 through this point.
You can also create a generic plane with PLN1.HIT[V1].XYZ and <0,0,1> as vector.

[JEFMAN]

You can also trying to use this Excel file, enter the XYZ values of hits of PLN1, and create a generic plane with values in the green box (you have to use solver and vba to make it work) - (it's the minimax tangent plane in versions after 2017 - I didn't find enough time to calculate the L2 constraint yet )

[AndersI]

The math professor strikes again! Thanks!

[JEFMAN]

AndersI :
I only calculate like this to :
1 - check PC-DMIS results,
2 - enhance the soft when something is missing...