# Point Cloud Basics

When I import from a CSV, I get a point cloud object. I an see operations to add and remove points to a point cloud. Are there are any surface or curve manipulations possibles?

Can I create a surface from a point cloud?
Can I crease a curve from a point cloud (or a set of points) without drawing point to point?

It depends on your modeling skills You might start with extracting / seperating the pointcloud points required for your modeling and go on turning the pointcloud in a shadable mesh. Then you usually use this mesh as a base object to create clean matching and watertight nurbs surfaces. For the first part, you might check out these commands on the mac version: `_Patch`, `_MeshPatch` (Do not just select all points, extract what is required first)

Try commands like `_PointCloudSection`, for interpolation use `_CurveThroughPt` with `Degree=3` then rebuild the outcome to your liking. To fit a line trough a set of points use `_LineThroughPt`

c.

Is there anything what would draw a nonplanar curve through a set of set of points? I.e., like drawing an interpolated curve without having to do each point manually.

I should be more specific–draw an interpolated curve where there is a single point along an axis.

(y,z) = f(x)
(x,y) = f(z)
(z,z) = f(z)

CurveThroughPt is what you are looking for

Thanks, the underscore was getting me. Was able to quickly draw them.

Does anyone know why CurveThroughPt creates a kink at the end of the curve. In this first image, I have curve generated with CurveThroughPt using interpolated points (red) and one manually drawn using InterpCrv (black).

The second image shows a series of curves with the same type of kink.

Possibly related, this file

Problem34.3dm (91.9 KB)

creates a loop of the type you that you might get with non-planar points—but the points are all in the same plane.

And this file shows the kink (cyan compared to drawn black) and the line goes past the end point.

(

Problem35.3dm (99.5 KB)

Such problems can happen if the spacing of the points is not constant. If you want to get it planar you might use `_SetPt`. To improve the curve quality, create degree 1 curves first, then rebuild to a higher degree. Try to create not too dense curves if you want to use them to surface the hull.

This is usually caused by duplicate points at the ends. Use `_SelDup` to find and delete them. If you get strange slopes within the curve, you might delete points which are too close together so the spacing is more even.

c.

It would be really useful to ignore duplicates to allow multiple data sets to be used.

I have been fixing the ends by chopping them off and redrawing but that is a real pain.

If you do not want to delete duplicate points, you might get better curve results using _CurveThroughPt _Degree=1 and set _CurveType=ControlPoint, then rebuild the resulting curves instead of creating interpolated curves through every point. The point spacing is uneven, so the interpolated curve results cannot be any different.

c.