About Power Fit

Power Fit accepts several input types.

To create a surface with Power Fit, you can select:

• One single cloud of points or one single mesh, or one single portion of those (datum mode only). Once selected, it is sent in the NoShow space. The name of the cloud of points or of the mesh is displayed in the dialog box, as Cloud.
• Or curves:
  • The curves form either a closed set of curves or an open set of curves. You can make the curves continuous either during their construction or using Clean Contour. Power Fit closes automatically the set of curves.
  • Those input curves are not modified and are sent to the NoShow space.
  • If a trimmed surface is created, the edges of the face are the curves computed from the input curves.
• Or a cloud of points or a mesh and curves.

Example of allowed curves:

• Closed set of curves:
  
  
• Open set of curves:
  
  
• Open set of curves with its topological closing line (no curve is created as such, but as the edge of the trimmed surface, if any):
  
  

Input curves can be processed differently according to options.

These options define the way the input curves are taken into account:

• As Constraint: The computed surface goes through them.
• Trim: The surface is computed, then the curves are projected onto it to trim it.
• or Selection: The computation is based on the points located inside the curves.

Continuity may be requested on the input curves regarding the surface to create:

• G-1: Free. Applies to the Trim or the Selection options.
• G0: Point continuity. Applies to the Constraint option.
• G1: Tangent continuity. Applies to the Constraint option.

The table below lists possible selections and options.

Input	Information	Output
Points or meshes		The surface is computed on the points. It is not trimmed.
Curves (outer boundary). No Points. or	Option: Constraint. Possible constraints: G0, G1.	The surface is computed on the curves. The curves become the edges of the surface.
Curves + points or	Option: Selection. Possible constraint: G-1.	The surface is computed on the points located inside the curves. The surface is not trimmed.
	Option: Trim. Possible constraint: G-1.	The surface is computed on the points. The curves are then projected on the surface to trim it.
	Option: Constraint. Possible constraints: G0 or G1.	The surface is computed on the points and the curves. The curves become the edges of the surface.

Power Fit does not support counterdraft.

When a counterdraft (orange arrow) or opposite points (purple arrows, the black arrow being the view direction)

are detected, a message is displayed in the dialog box, and no surface is computed. You can solve the problem by activating a portion of the cloud of points and restarting the computation.

When Power Fit is used to compute a trimmed surface from the points of a cloud of points and curves that form the surface boundaries, these curves define a prismatic trap with infinite height and a view direction. The points used for the computation are all the points contained in this trap. Therefore, counterdraft or opposite points may alter the computation.

Power Fit can select the required points up to a certain level:

• The points are separated into two zones, according to the direction of the normal of the triangles. This selection is easy in the above cases (the equator line is the separation between the two zones for the counterdraft, for the opposite points, the zones are already well delimited). The incorrect zone is not taken into account in the computation.
• The selection is harder when points belong to two zones, defined by the normal of their triangles, both zones containing points that should not be taken into account. Such cases are not yet dealt with successfully.
• In short, the points that Power Fit recognizes as unwanted for the computation are correctly eliminated. However, some points may still be taken into account, whereas they should not. This may lead to a defective result. In such cases, you should activate yourself the requested zone, with Activate.
• This is possible with meshes, not with cloud of points.
• All triangles considered belong to the same mesh and their orientation is coherent.