OPTIONS:

-u units_str

Units of obj file where units_str can be any valid BRL-CAD unit such as one of the following {m|cm|mm|ft|in} or specify a conversion factor from obj file units to mm.

-o open_bot_type

Type of bot to create when the primitive is not a closed volume. open_bot_type can be {s|p|n} where ... s = surface bot, p = plate bot, n = plate-nocos bot. Generally use 'surface bot' if open surface thickness is irrelevant or the purpose of the resulting model is strictly visualization. Use 'plate bot' or 'plate-nocos bot' when open surfaces must have a defined thickness. Note: An incorrect plate thickness can create geometry overlaps. Use the '-h' option to define plate thickness.

-h plate_thickness

Plate thickness in mm units of plate or plate-nocos bots created when the bot is not a closed volume. This option is ignored if the open_bot_type is 'surface bot'.

-c

Continue processing on nmg-bomb. If this option is set and an nmg-bomb occurs (i.e. fatal error during processing nmg or bot-via-nmg) conversion will fall-back to outputing the grouping to 'native-bot' and then continue processing the next grouping. If this option is not set and an nmg-bomb occurs then all processing will stop and the converter will exit.

-i

Ignore normals defined in the obj file when the conversion mode is 'native-bots'. This option has no effect when the conversion mode is 'nmg' or 'bot-via-nmg' since in these modes provided normals are always ignored.

-p

Plot open edges when creating bots which are not a closed volume. A plot/overlay (.pl) file will be created with the same name as the bot primitive and be placed in the current directory. If a plot file already exists, it will be overwritten. Closed edges are closed but open edges are not necessarily open. This is due to limitations of the algorithm for identifying open edges.

-d

Output debug information to stderr stream. An extremely large amount of information will be output. It is strongly suggested strerr be piped to a file.

-v

Output verbose user information to stderr stream. There are different levels of verbose output where higher levels increase the amount of output information. Each occurrence of this option in the parameter list increases the level. A large amount of information will be output so piping stderr to a file is highly recommended. Verbose messages add warning and detailed conversion status messages to the default status and error messages. Verbose must be enabled for warning messages to be reported.

-g grouping_option

Choose which face grouping, as defined in the obj file, to use to create the BRL-CAD primitives. The grouping_option may be one of {g|o|m|t|n} where ... g = group (default), o = object, m = material, t = texture, n = none. Choose a grouping option which will produce the appropriate primitives for the intended use of the resulting model. Typically not all groupings exist in every obj file. Do not choose 'none' as the grouping option unless you have a specific need for no grouping. Choosing 'none' for a large conversion will significantly increase the time and system memory required for a conversion to complete. Choosing a grouping which does not exist in the obj file has the same effect as choosing 'none'. If you are unsure of which grouping to choose, perform some trial conversions in the 'native-bot' conversion mode using each of the grouping options. I may also be helpful to enable level two verbose messages and pipe stderr to a log file. At the beginning of the log file will be a section called 'OBJ FILE CONTENTS' which lists how many and the names of the groupings in the obj file. Note: It is possible for a single grouping to produce up to four primitives due to the four possible face types that can exist in an obj file. The values of the index numbers appended to the end of the primitive names will give an indication if this has occurred.

-m mode_option

Choose the conversion mode. The mode_option may be one of {b|n|v} where ... b = bot 'native-bot', n = nmg, v = bot-via-nmg (default). The 'bot-via-nmg' mode is the best option for creating solids (i.e. volume-mode-bots). The 'native-bot' mode is best for a comparatively quick conversion where creating solids is not the highest priority and the faces provided in the obj file are known to be simple and convex. The 'native-bot' mode will attempt to identify surface closure (i.e. solids) but is not as robust as 'bot-via-nmg'. The 'native-bot' mode is the only choice if it is desired to use normals from the obj file such as in cases where the normals are smoothing normals.

-t distance_tolerance

Maximum distance, in mm units, where two vertices are considered the same. The default is 0.0005mm which matches the raytracer default distance tolerance. Do not change this value unless you also change the raytracer distance tolerance.

-x rt_debug_flag

Specifies debug bits (see raytrace.h)

-X NMG_debug_flag

Specifies debug bits for NMG's (see nmg.h)

obj_filename

The path and file name of the input WaveFront Object file.

BRL-CAD_g_filename

The path and file name of the output BRL-CAD database file. If this file already exists, it will be overwritten.