CreateMultipleSurfaces.vbs

Description

This script creates multiple surfaces from a large selection of lines. It will create triangular surfaces from 3 lines where possible first, then it will create quadrilateral surfaces from 4 lines. The script will avoid creating coincident surfaces and will check for the presence of triangular surfaces before creating a quadrilateral surface coincident with existing triangular surfaces. This is particularly useful for creating multiple surfaces quickly where geometry from a CAD package has imported just as a frame of lines and points. It can also be useful for reconstructing surfaces that have been deleted to resolve connectivity problems in the underlying points and lines.

Where three lines would create a zero area triangle, the script will add these three lines to a group “LinesBridgingAnotherPairOfLines” and will refrain from trying to create a triangular surface from these lines.

Speed

The default behaviour is that the script will create both triangular surfaces and quadrilateral surfaces and it will avoid create them in the same space to an extent. However, mainly to improve speed, if you wish to turn off the creation of triangular surfaces, set “CrtTrnglSrfcOptn” to 0 or if you wish to turn off the creation of quadrilateral surfaces, set “CrtQudrltrlSrfcOptn” to 0.

If you just select lines that will create triangles only it will take longer, or just select lines that will create quadrilaterals only, the script will be quicker than for a mixture. For example,

a) Creating only quadrilateral surfaces from 100 lines (2D grid with 58 points creating 43 surfaces) may take 2 minutes with the default settings. If the option to consider creating triangular surfaces is turned off, this same grid of lines may be of the order of 25% quicker.

b) Creating only triangular surfaces from 100 lines (2D grid with 42 points) may take 12 minutes. If the option to consider creating quadrilaterals, is turned off this may be of the order of 85% quicker.

Other general aspects affecting speed:

· The more surfaces to be created, the longer it will take

· The more points underlying the selected lines, the longer it will take

· The more lines common to each point, the longer it will take

For example,

a) 100 lines (2D grid with 53 points and 8 lines that cannot be used, creating 48 surfaces) may take 6 minutes

b) 1000 lines (2D grid with 499 points and 100 lines that cannot be used) may take 2 hours by comparison on the same PC.

Other Notes

2) THIS SCRIPT IS NOT PART OF LUSAS SOFTWARE AND AS SUCH IS NOT QUALITY APPROVED OR SUPPORTED. IT IS PROVIDED ON AN AS IS BASIS FOR DEMONSTRATION PURPOSES ONLY.

3) The script will only try to create surfaces from the selected lines.

4) If only three or four lines are selected, the script will try to create a single surface and will provide a message to the user if this fails which can be helpful in highlighting where the user may have previously been unable to create a surface due to connectivity problems.

5) This script will not create surfaces from 5 or more lines.

6) Remember to check and adjust the surface normal directions and surface axes as necessary.