OFFSETSURF

Offsets triangulated surfaces in the direction of the surface outward normal, i.e., normal surface motion. For each node a ‘synthetic’ unit outward normal N is computed based on the weighted average angle of the normals of the triangles shared by that node. old_cmo is the surface to be used in generating the offset surface. new_cmo is the name of the new surface.

To add the nodes in the new surface to the main mesh object use the copypts command. To add the new surface to the main mesh object use a surface command with new_cmo as the sheet name (e.g. surface/s2d/bndy_typedist is given in user coordinates (i.e. whatever units the old_cmo mesh object was defined in.) The new node coordinates, R_new, are computed using the formula:

R_new = R_old + dist * N_node

Various keywords control the behavior of the command:

The following keywords can appear in the 5th, 6th, 7th or 8th argument position.

keepatt, keep_angle -  Compute node angle weighted normals and keep the vector components in three scalar attributes x_n_norm, y_n_norm, z_n_norm

keep_area - Compute node area weighted normals and keep the vector components in three scalar attributes, x_n_norm, y_n_norm, z_n_norm

xzero  - Compute the full offset direction vector but set x component to zero

yzero  - Compute the full offset direction vector but set x component to zero

zzero  - Compute the full offset direction vector but set x component to zero

The following keywords can appear in the 5th argument position.

xy, xz, yx, yz, zx, zy - these keywords constrain the offset to be parallel to the specified plane. These arguments can be used with a line type mesh object to constrain the offset to a particular plane.

FORMAT:  

offsetsurf/new_cmo/old_cmo/dist/keyword

 

EXAMPLES:

offsetsurf/mo_out/cmo_in/d

offset a triangulated surface a distance d using angle weighted normals

offsetsurf/cmo_out / cmo_in / d / keep_area 

offset using area weighted normals

offsetsurf/mo_out/cmo_in/d/[xy,xz,yx,yz,zx,zy]

offset a line cmo a distance d in a direction parallel to the specified plane

offsetsurf/mo_out/cmo_in/d/x y z

offset a line cmo a distance d in the direction specified by the vector (x,y,z)