Constraining a surface through a set of points

In this task you will apply a controlled modification to a surface by applying the Passing Through Points constraint of the Advanced GSM command. You can accomplish this task by opening file "ThroughPoints.e3".

1	Start the Advanced GSM command. Under Entities to Be Modified, set Entities to Surfaces and select the surface.
2	Under the Preserving node, in the Preserving drop-down list select Curves. Click on the curves to be preserved: in this case, the surface boundary. In the Constraint drop-down list, select the constraint to be applied along the curves to be preserved (position, tangency, curvature or projection — to avoid changes along a select direction). In this case, select Keep position.
3	Under Passing Through, set Passing Through to Points.
4	In the Group 1 drop-down list, you can choose the type of points to be selected: Standalone Free points. Points on Surface Points lying on a surface. Points on Curve Points lying on a curve. ASCII File Point coordinates to be read in an ASCII file to be selected (for details see "Reading point constraints from an ASCII file"). In this case, choose Standalone and select the points you want the resulting surface to be through. In the Constraint drop-down list which shows up on the model, you can choose the continuity constraints to be applied along the points the resulting surface must be through: position, tangency or curvature. In this case, select Target position.
5	In the Projection type drop-down list, you can select the projection to be used in the controlled modification: Normal the points will be projected normally onto the surface. Flat the points will be projected onto the surface using a linear projection along a specified direction. Single curvature the points will be projected onto the surface using a cylindrical projection for which you will have to specify the axis. Double curvature the points will be projected onto the surface using a spherical projection for which you will have to specify the center. In this case, select Normal.
6	Click the Preview button () to assess the result.
7	Click or to confirm your selections and modify the shape of the surface.