# challenge..

#### james.lynch

##### New member
to create a triangular pattern of points ona complex 3d surface/quilt such that if a Curve On Surface (or projected curve) was created between 2 adjacent points, the curve distance would be say 5 mm..

ISDX offset COS not allowed!

cheers,

James

#### james.lynch

##### New member
nobody? come on people! I know it can be done! (I just don't know how!
)

#### jrobi

##### New member
I think youd have to project the points.

#### james.lynch

##### New member
but there in lies the problem! I have no problem creating the points on a plane, then using them to create the points on a surface, the problem is that it's no a correct solution to my problem..

the distance between the projected points is no longer 5mm..

James

#### djor

##### New member
James,

I don't think you con get there with just the points by themselves. If you use the Wrap tool to make formed datum curves on the surface then the curve ends could be used to place the points.

#### wsylvester

##### New member
James,

What no answers from ptcuser.org

#### jrobi

##### New member
hmmm- got me there jimmy....I would suggest projecting curves onto surface, and patterning the points along the curves...that would allow the maintained distance of 5mm...reminds me of the days of reverse engineering printless5axis tooling from point clouds...ahhhhhh, glad its over

##### Moderator
Mathematically, I don't think you can maintain an exact spacing between all points unless:

a) the projected surface is planar
or
b) the projected surface has a constant curvature value(a sphere)

As soon as you get into any other shaped surface, some points will need to be closer or father apart than others (to create the curvature)

Consider taking a thousand pieces of paper shaped like equilateral triangles with 5 mm sides and trying to approximate your surface with them. You might be able to get something close to what you want, but the peaks and valleys will probably be higher or lower than what you want.

Just a thought...

-Brian

damnit brian....

#### Dell_Boy

##### New member
Brian is basically correct with just one exception

Points on a plane is the most basic solution.

Three of the Euclid solids, tetrahedron, octahedron, and icosahedron
are spherically based convex arrangements of equilateral triangles.

By taking sub-sections of these solids you may theoretically be able to
arrange them into a multi-concave/convex surface that meets the
original requirements but at best they can only be described as
highly restricted special cases.

DB

#### dalex

##### New member
James,

Try projecting the pattern of curves onto the surface. Then use BMX to optimize the length of each of the individual projected curves to the desired length. It will be time consuming if you have a lot of curvesbut will give you the desired curve lengths.

#### james.lynch

##### New member
I havn't got the use of BMX for this project unfortunately... I think the wrap comand is the way to go!

thanks for all the help everybody!

if anybody comes up with a better way by all means let me know!

Cheers,

James

#### tcorbera

##### New member
Big challenge but, there's no way to do this!

It's only possible on 2 directions not on 3! Except for spherical or cylindrical surfaces.

If you really want to do this, try to call Mr Houdini (joke!!!)

Tryto export your surface on a 3D Finite element CAD software.

Mesh it with uniform triangles (same size 5x5x5).

Export the resulting mesh and open it on Pro E.

For me it's the best approximation.

Thomas from "la France"

#### jeff4136

##### New member
Wonder of there's any future in using datum points on curves (offset: real) for such solutions...