Page 26 Modeling Trog: Arms

Arms

Open file trog7.3dm or merge t7.3dm

Overview: What we have here is the profile curves for the arm. If you were doing this yourself you would either scan in a sketch or I usually just draw some curves that look approximately right. However the thing to note here is that I had end osnap on and ended the curves at the same point.

The geometry of the arm is going to be created from the using the command CSec which is a tool that creates section curves, the shapes of which are determined from the profile curves.

This would also be a good time to clean up the layers and discard any layers no longer needed, like leg curves, array, guide and trim curves. Make a layer called 'leg' and hide it and ChangeLayer the leg to the hidden layer. Also give your layers some colors.

Make the layer called 'section curves' and make it the current layer. Turn on layer 'annotate'.

With 'Point' Osnap on, hit CSec and select the profile curves in order according to the numbers on the 'annotate' layer and hit enter.

Note: If the curves had been picked in the opposite order the curves would have been going in the opposite direction and the surface normal's resulting from lofting the curves would have been flipped in towards the center of the arm.

When prompted for 'Start of cross-section line ( Closed=Yes ):' snap to the points on the layer 'annotate' starting with the top left point and ending with the point below it to create the CSec sections.

Note: The curves created are basically at areas that denote change in the profile curves. Where the section curves are placed is important because we need section curves wherever there are definite transitions in the profile curves (like around the elbow) in either the top or front views.