Extract Z coordinate from the NURBS surface by moving the mouse

Rhino Rhino for Windows
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1

Dear

I imported the point cloud data into the Rhinoceros software and created a NURBS surface. I have a point coordinate with the X and Y coordinates available, but I want to know that what is the Z coordinate for this point on the new created NURBS surface.

How could I understand the Z coordinate for a specific point with the available X and Y coordinates on the new created NURBS surface? When I moved on the mouse on the NURBS surface, it does not show me the Z coordinates during my movement on the surface.

I would be thankful if you may guide me

Thanks for your response

Best regards

Amir Farshadfar

2

You’re probably looking for the command PointsFromUV. There’s no way to see that information as a mouse tool tip as far as I know.

3

Hi Amir -

You could create a vertical line from the x,y position and intersect that with the object to get a point. Selecting that point and using the What command will then give you the z value.
If the point that you are evaluating is on one of the points of the point cloud, you can sub-object select the point and run What on that directly.
-wim
-wim

4

Hi Amir - EvaluatePt with the OnSrf Osnap, possibly combined with others as needed, may help here.

-Pascal

5

Thanks for your response. Could you please tell me what is U and V values and how should I know them?

7

Thanks for your guidance. How could I understand the exact coordinate of the intersection of the line with the NURBS surface?

When I draw a line and intersect it with the surface and choose the “point” option to draw a point and activate the “onsrf” and “intersection” option from the Osnap, I can just draw a point in near of the intersection and not just exactly at the intersection. How could I do that?

When I choose the “point” option to draw a point and activate the “onsrf” and “intersection” option from the Osnap, and define a X and Y coordinate in the common line, it just draw a point away from the defined X and Y coordinate!

I need the exact intersection of the line with the surface or I need to draw a line or point with the X and Y coordinate on the NURBS surface and give it back to me the Z coordinate of the defined coordinate.

8

Thanks for your response and guidance. When I type the “EvaluatePt” and activate the “onsrf” and “Osnap” options, it shows me the full coordinates for my mouse movement, but I could not type a X and Y value and give it back to me its Z coordinate. When I type a X and Y coordinates, it shows a point away from my defined X and Y coordinate with the related Z. I want the software shows me the Z coordinate of my defined X and Y coordinate.
How could I define a determined X and Y value by the option “EvaluatePt”, and give it back to me the Z coordinate of the specified coordinate, on the selected NURBS surface?

9

Hi Amir -

With both selected, run the Intersect command.
-wim

10

An alternative is create or use an existing point at the desired x,y position.
Project that point onto the surface.
EvaluatePt the projected point.

11

You can try this quickie scriptlet:

EvalProjZOnSrf.py (691 Bytes)