Moving a point on a surface in vertical and horizontal directions

I would like to move a point on a surface [a shoe last surface] in vertical and horizontal directions - not in u-v directions [as in this video:]. My solution was to create some horizontal lines and to find their intersection with the surface. Moving the lines on horizontal or vertical will move the intersection points but there are situations in practice when this method doesn’t work well [when there are big curvatures] Do you have any other suggestion?
Thank you in advance!
Move point.3dm (411.7 KB)

@PetcuDaniel did you actually try to replicate what you see in the video?

You seem to be talking about how to evaluate a surface, in this case the shoe last. If so, the method is quite simple: (510.0 KB)

I ran the flip command on your surface so that the vector points away from the last

No, I don’t want to replicate because in the video the point is moving on the U-V surface coordinates!
I need for the point to move on surface but in the OZ - OY direction as in the attached video. My solution was to move an horizontal line [OX direction]. The point which is moving on the attached video represent the intersection between surface and horizontal line [OX]. Curios to see if there is a better and faster solution. When the point is moved after U-V surface direction is very hard to target a precis pozition. Moving it ON THE SURFACE but after OZ-OY is more intuitive! Hope I’ve explained well - if not, please ask me!
Thanks in advance!

Here a .gif format of the video


Where is your solution?

I put both solutions in the same file. Try to ‘catch’ one point from one method with the point generated through other method. In the ‘u-v’ method. My experience tells it is easier to catch through OZ-OY method the point generated through U-V than vice-versa. I like the ‘reparametrize’ but I don’t understand how can I apply it to the OZ-OY method. As I have many points to manage and I can’t manage Grasshopper at a higher level My question is if there is other simpler that mine!

evaluatesrf_example (511.5 KB)

Maybe this help you (505.7 KB)

Thank you!
It ask me to install Pufferfish ( which is a problem to me as I am tempted to rely only on Grasshopper in order to be sure I’ll be able to use long time. Can be a version only in Grasshopper?

Pufferfish used to find bounding rectangle ; you can use some components to find the bounding rectangle

Thank you, I’ll try! (509.7 KB)


I apologize, this whole time it has remained unclear to me what you wanted.

I saw Seghier’s help file, and was still unclear haha :sweat_smile: but I think you got enough material

If your goal was for your point (found on the last’s surface) to be manipulated in a parallel/orthographic fashion then I totally missed that part in your original post.

Try this:
evaluatesrf_example (524.9 KB)


Thank you @seghierkhaled and @corellaman and sorry for my late feedback!
I found very useful both solutions with new elements to me [as a novice user of Grasshopper]!
Thank you again!

@seghierkhaled, @corellaman

One problem here is in the high curvature surface’s regions as in the heel and toe. As you can see with the red arrows it is hard to move point in the most proximal region of the heel. I will work with a section surface defined by the most distal an most proximal last’s surface curves.

One more asking, if possible! How will you manage to move 3 points in the horizontal and vertical directions [ parallel/orthographic ]. I’m asking you because still I can’t manage lists, trees,… in an efficient way. At this moment I will copy/paste the same code for each point which I have to move

Thank you for your help!
Have a nice weekend!

Some modifications which works well for me! (16.0 KB)
evaluateSrfOzy.3dm (791.6 KB)