Explicit specification of LOD tolerances in JT export

Command-line utility: AlToJt

For the AlToJt translator, the tessellation tolerance for the first level of detail is specified through argument -t <tol> (where tol is the tolerance value expressed in centimeters).

We added two optional arguments, -t1t and -t2t, to specify absolute tolerance values for the second and third levels of detail respectively.

Hence, a command line specifying all three tessellation tolerances looks like this:

AltoJt -t 0.1 -t1t0.5 -t2t1.0 -i <input wire file> -o <output Jt file>

If any of -t , -t1t , or -t2t is not specified, default values of 0.01 cm, 0.025 cm, and 0.1 cm are used respectively.

If using a scheme configuration file to provide the argument values, the format is as follows:

; this ui-symbol controls Tessellation Tolerance for first LOD
 (ui-symbol "mo_eai_tesselation_tol" 	0.1)
; this ui-symbol controls Tessellation Tolerance for second LOD
 (ui-symbol "mo_eai_tesselation_tol1" 	0.5)
; this ui-symbol controls Tessellation Tolerance for third LOD
 (ui-symbol "mo_eai_tesselation_tol2" 	1.0)

Assigning labels to LODs

If you want, you can assign labels to the levels of detail. These labels are saved in the JT file, and appear in the JT Export option window.

There are two ways of assigning labels:

1. By setting these environment variables to the required names:
   • ALIAS_JT_LOD0_LABEL (first LOD)
   • ALIAS_JT_LOD1_LABEL (second LOD)
   • ALIAS_JT_LOD2_LABEL (third LOD)

   For example: ALIAS_JT_LOD0_LABEL=Fine

2. By un-commenting and setting the following name-value pairs in the scheme configuration file:

   (ui-symbol "mo_eai_tess_lod0_label" "Fine")
   (ui-symbol "mo_eai_tess_lod1_label" "Medium")
   (ui-symbol "mo_eai_tess_lod2_label" "Coarse")
   

   Labels specified through a scheme configuration file override the environment variables when the scheme file is:

   • Specified as the value of the -f argument in the AlToJt command line.
   • Called dt_jt.v.scm and located in ALIAS_LOCATION\Scheme\Modeling. This file provides the default values for the JT Export options in the Alias application. You need administrator privileges to modify it.
     NoteALIAS_LOCATION is where Alias is installed, typically Program Files\Autodesk\Alias2013

Only the first 15 characters of the label names appear in the option window, although all are saved in the JT file. Allowed characters are letters (upper and lower case), numbers, underscore ("_") and white spaces.