Where can I increase the default value of the number of control points that appear for a surface when one selects surface and hits F10 ?

I have a diagonal edge and need to pull the surface formed by patch down tighter to it, or can I increase the density just parallel to and in the area of the edge. Rest of surface is parallel to the control point grid but using those I have at that edge sees a bad ripple occur when being pulled in.

Control points are an intrinsic part of the surface structure (like curve control points) and unlike the isocurve display, one cannot simply “add density”. What you can do:

Rebuild the surface with more points in one direction or both. That
MAY change the surface significantly elsewhere however, depending
on the surface configuration and number of points.

Add knots or rows of control points locally : with the commands
InsertKnot and/or InsertControlPoint you can add knots or rows of
control points to a surface locally where you need more
"flexibility" without radically changing the surface further away.
You need to choose the direction (u or v) for the additional row(s).

Hi,
I had wondered on insertKnot, best to do this after all other tweaking doen as one ends up with a lot more control points to push and pull elsewhere as a result.

What is the difference between InsertKnot and InsertControlPoint as they seem to give me the same extra points and lines.

InsertKnot does not change the shape of the curve or surface at all. On the other hand, it will rearrange rows of points, including the new one added with the knot, to make this happen. Except in special cases, knots will not be at the same locations as control points- i.e. you cannot choose where the new points will go, exactly.
InsertControlPoint inserts points exactly where you put them, but except in special cases will change the shape of the curve or surface… a little, or a lot. Currently, The output from InsertControlPoint always has uniform knots.

@pascal Thank you for that precise description and another bit of knowledge to be stored in the repository for future use… The repository seems to be getting more crowded these days, probably a consequence of more and more things to store as well as the storage space that is continually diminishing… :neckbeard:

Why does InsertControlPoint and InsertKink seemingly have the same effect? (What I want is the right-most effect, but the only way to get that is via Rebuild and that changes the V distribution of control points, even if I make sure the counts are the same.)

InsertControlPoint, InsertKink and InsertKnot do not change the degree of curve or surface

The surfaces on the left and center are degree 1 in U. Using InsertControlPoint or InsertKnot keeps them as degree 1 but increases the number of spans. I assume the surface on the right is degree 2 in U. That is why it behaves differently.

You may want to investigate ChangeDegree and RebuildUV.

Hello - InsertKink always inserts a fully multiple knot, regardless of degree- when the thing is degree 1, that also happens with InsertKnot since 1= fully multiple. So, yeah, what David said - ChhangeDegree - that keeps it a single span as well, which is (usually) better than inserting knots for simple shapes.

ChangeDegree is good when inserting knots/control points to single span curves and surfaces if the desire is to retain a single span curve or surface…

InsertKnot or InsertControlPoint are the better commands to use to add knots and control points to a mult-span curve or surface while retaining the degree of the curve or surface.

The results of ChangeDegree may be different than what is desired shen starting with a multi-span curve or surface. When increasing the degree with ChangeDegree if Deformable=No is used then the result is higher degree multi-span curve with multiknots betwen the spans which exactly the same continuity between spans the the original lower multi-degree curve. The increase in the number of control points will be equal to the difference in degree multiplied by the number of spans. I have not found a use for this result in my work. In the same situation but with Deformable=Yes the number of control points will be increased by the difference in degree, independent of the number of spans but the shape of the curve or surface will usually be changed.