Command line options

Overview

Option	Description	Status
-2mm	convert model to millimetre
-ac	determine accuracy of model
-as	"explode" assembly
-bs	display base surfaces of faces
-c	use indicated configuration file
-ca	create assembly for multi-solids
-cgi	create cgi output
-cp	create pcurves	unsafe
-e2b	convert elementary to b-spline surfaces	unsafe
-ex	extrapolate b-spline surfaces	unsafe
-f2m	convert faceted_brep to manifold_surface/solid	unsafe
-fb	filter breps	unsafe
-fc	filter curve_bounded_surfaces	unsafe
-ff	filter faces	unsafe
-fmt	reformat input STEP file
-g2m	convert geo_bounded surface to manifold	unsafe
-h2l	convert hyperbola/parabola to line
-i	set the number of iso lines to display
-l	use logfile specified
-m2g	convert manifold_surface to geo_bounded	unsafe
-m2s	convert mapped_item to shape_rep_rel	unsafe
-ncs	normalize coordinate system	unsafe
-np	ignore pcurves if present
-nr	do not repair anything
-ns	run in batch mode
-nt	do not display text section
-o	load specified file into text section
-rh	restructure hybrid models	unsafe
-rmax	approximate circles with big radius	unsafe
-rmg	remove styling from input file
-rp	remove pcurves
-rs	rotate seams of periodic surfaces	unsafe
-rvd	remove voids in breps
-sa	set accuracy to value given
-scb	set colors for breps	unsafe
-sp	split assembly into multiple files	unsafe
-u	check/repair consistency of input
-u	more hazardous repairs	unsafe
-v	set verbosity of error messages
-va	check vertex angles

Standard Options

Note: The 'lv' tool configures ("binds") itself for a specific EXPRESS schema, aka STEP application protocol (e.g., AP 214, AP 203). The EXPRESS schema is selected according to the information given in the STEP file's header. If the STEP file does not match the EXPRESS schema which it claims it conforms to, this usually results in syntax error messages printed during loading. In such cases, 'lv' might abort after having read the STEP file. See section on Runtime environment for some more details.

More options can be supplied on the command line. These include:

• -2mm: "to millimetre" converts the given input model to a millimetre basis. In case the input model's geometry was defined on a different basis (e.g. inch, metre), a modified STEP file will be written.
  Note: This option can be combined with most of the other modification-type options, except for option -sp (unsafe option).

• -ac: "accuracy" if geometry and topology are not consistent within the accuracy stated in the STEP file, this option makes 'lv' try to find a larger accuracy value that satisfies the checked conditions. If successful, the value will be encoded in the "-mod.stp" file. However, relaxation of the accuracy will only be performed within reasonable limits. Accuracy values beyond 1mm are considered unreasonable.

• -as: "assembly decomposition" when the input STEP file contains an assembly, the option will create an output file that does not contain assembly information. Rather, all geometry is duplicated and moved so that it explicitely appears where it would be in the assembly context. Thus, this option may cause a considerable increase in file size. Its purpose is primarily to help post processors that do not support assemblies to read assembly input. If the assembly contains mixed geometry types (e.g. wireframe, solids, surfaces), the way the output is written can be controlled as follows:

  • -as1: write "classical" OR-encoding (single product, multiple shape_definition_representations, multiple specialized shape_representations)

  • -as2: write according to "STEPnet agreement" using shape_representation_relationship

  • -as3: write according to "ProSTEP Round Table agreement" using a plain shape_representation

  Note 1: options as1-3 can also be used to restructure non-assembly, mixed model input files.
  Note 2: see also -sp and -rh (unsafe options).
  Note 3: A known bug is that this option might not work properly if the input model is not defined on a millimetre basis. Therefore it is recommended to combine this option with the option -2mm.

• -bs: "base_surfaces" display base surfaces for faces and curve_bounded_surfaces in addition to the trimmed face/curve_bounded_surface. This is only recommended for relatively small STEP files.
  Note: In the case of unlimited base surfaces, these are displayed within the range [-10,10], which is chosen arbitrarily.

• -c: "configuration file" lets 'lv' use the colors defined in the given file, instead of either the colors given in the file 'lv_cfg.stp' in 'lv'`s base directory or the default colors.
  The actual name of the configuration file is expected as the next argument following the "-c" argument (e.g. "lv -c mycolors.cfg test.stp").
  Note 1: The configuration file's syntax is described in the file 'lv_cfg.expr' in 'lv'`s base directory.
  Note 2: If an additional '+' is given, like in "-c+ ", then the colors in the configuration file will not be overridden by colors defined in the product to be displayed ("force color" option).

• -ca: "create assembly" modify the input file so that no more multi-solid shape_representations are present. Shape representations that contain multiple solids are split and connected via an assembly structure. This option is useful if the target system tries to glue the solids in a shape_representation together, but the intent is to be able to handle them separately after the transfer.

• -cgi: "create cgi" output. Any output on the terminal or in the logfile will have HTML line wrap commands inserted at a newline, which makes the text look prettier in a HTML browser.
  Note: in addition to -cgi, you should supply -v4 or lower (because printing of progress is not useful in the HTML viewer, and not affected). Also, -ns -nr are typically useful.

• -fmt: "reformat" just writes the given input STEP file back as a "-mod.stp" file, without any modification. This option is suitable to reformat the input file.
  Note 1: When combined with option -ns, a true batch-type operation without a connection to an X server is possible.
  Note 2: This is the only case where 'lv' writes a STEP file even if the input STEP file contains syntax errors.
  

• -h2l: "convert hyperbola/parabola to line" in combination with -u -ns, 'lv' checks if any hyperbola or parabola used to define the geometry of an edge_curve can be replaced by a line for the given distance_accuracy value, and if yes, does so. This is a possible fix for problems with these curves in cases where they have numerically difficult properties.
  If an additional '+' is given ("force", "-h2l+"), the conversion is forced: If the curve cannot be replaced by a line within the given distance_accuracy, then it gets replaced by a b-spline of degree 1 with 10 control points (regardless of whether the deviation is then within the distance accuracy or not).
  Note: This option is deactivated if -u3 is given.

• -i: "isocount" affects the number of isoparametric lines that are used to represent surfaces or faces in the graphical display.
  The required number of isolines should be specified immediately after the "-i", without a blank (e.g., "-i7"). Values between 0 and 99 may be specified.
  Depending on the properties of the parameter space, the number of isolines actually displayed can be lower.
  Note: If the STEP file contains presentation information that specifies the number of isolines for presentation, the value given in the STEP file takes precedence over the value given with this option. An additional '+' character can be given with the -i option in order to change this behaviour, so that the value given with -i always applies. Example: "-i5+" - force an 5x5 isoline mesh

• -l: "logfile" specifies a name for a logfile into which any detected problems are written.
  The actual name of the logfile is expected as the next argument following the "-l" argument (e.g. "lv -l test.log test.stp"). If this parameter is omitted, but the graphical display is used, the following defaults apply:
  1. "name of the STEP input file".lvlog
  2. ./lv.log,
  3. /tmp/lv.log.
  They are tried in this order, the first writable file will be used. If neither is possible, or graphical display is not used, the standard output will be used.

• -np: "no pcurve" if a STEP file is known or believed to have wrong parameter space curves (pcurves), this option tells 'lv' to ignore any pcurve representations within surface_curves, using the 3D curve only. This may then get some useful results out of the data.
  Note: Due to the odds with parameter space representations in STEP (relevance of unit context etc.), problems in these representations are found every now and again...

• -nr: "no repair" 'lv' does not write a 'repaired' file. 'lv' can fix (or believes to be able to fix) a number of problems and write a new STEP file containing the fixes. Such a file will have the name "-mod.stp" appended to the original name (see description at -ns option). With -nr, this is prevented.

• -ns: "no show" do not launch a graphical display of the geometry. Useful if a batch-type checking/repairing/ conversion operation is desired.

  The repair facility is the primary purpose of this option. With -ns, many of the problems reported in the logfile will be fixed by 'lv' (e.g., problems that are reported when -u is also supplied on the command line). The modified data will be written to a file whose name is derived from the input STEP file name, but has "-mod.stp" appended to its name.
  Note 1: If the input file already ends in "-mod.stp", the modified file will have the ending "-mod2.stp" (..."-mod3.stp" etc). This allows to concatenate several modification steps without ending up with very long file names. However, no check is made whether the computed output file name already exists, and in such cases, the existing file gets overwritten.
  Note 2: Repairs are never done if graphical display is enabled, because the displayed file in "STEPfile" mode would then not reflect the repaired instance set. However, if -ns is provided, repairing is done by default. In case this is not desired (e.g., because only checking is desired), the additional option -nr should be supplied.
  Note 3: There are some other modification-type options where -ns is implied and needs not to be specified in addition.
  Note 4: Repairing implies that any instances that violate the underlying data model (schema) in an obvious manner get erased.

• -nt: "no text" launch 'lv' with the geometry display only, without the text section.
  The text section can be activated later, as described in the Menu functions and options section.

• -o: "other_file" specifies a file that is loaded into the text section.
  The name of the file to load is expected as the next argument following the "-o" argument (e.g. "lv -o cad.log test.stp"). 'lv'`s layout is also changed to allow an 80-column text to be entirely visible.

• -rmg: "remove mdgpr" remove all instances of mechanical_design_geometric_presentation_representation. The purpose is to help post processors that have this entity not (yet) implemented.

• -rp: "remove pcurves" eliminate surface_curves and pcurves that are used to define the geometry of the edges in a STEP file, and write a modified file.
  Note: Can be used to prevent faulty pcurves in the STEP file to be processed by a STEP postprocessor.

• -rvd: "remove voids" replace all brep_with_voids by manifold_solid_breps, i.e., delete all voids. The intention is to reduce the STEP file size.

• -sa: "set accuracy" set all distance_accuracy values to the explicit value given in mm (e.g., -sa=0.01).
  Only values greater than zero and less or equal to 1mm are accepted. The given value is also used, e.g., for -u operations.

• -u: "usability" check consistency of geometry. Possible levels:
  

  • -u0: no check (default in case of non-interactive operation).

  • -u1: basic checks (recommended). These checks include
    • checks for structure violations (wrong references etc)
    • whether vertices lie on edges (VertexEdgeGap)
    • whether vertices lie on surfaces (VertexFaceGap)
    • whether edges lie on surfaces (EdgeFaceGap)
    • whether edges are shorter than the accuracy (EdgeLength)

  • -u2 (default, and minimal, -u level if the graphical display is enabled, i.e., no repairing activities are enabled and the option -ns is not provided): deep checks. These include
    • whether loops are "slim" within the accuracy (related to FaceArea)

  • -u3: extended checks. These work just like -u2, but for the edge length and edge on surface tests, 100 instead of 10 sampling points per edge are taken (which leads to more precise results, but requires more computation time)

    Note: In case 'lv' is used interactively, -u3 is actually the only one of the -u levels that changes the program behaviour, since otherwise -u2 is the default and overrides any lower levels that might be provided explicitely.

  Any error messages resulting from these checks are indicating distances in mm, regardless of the units used in the STEP file.
  If "-mod.stp" files are written after these checks, 'lv' has eliminated structure violating instances, short edges or slim edge_loops

• -v: "verbosity" the level of detail in error messages. The lower the level, the lesser messages are put into the logfile. Information about the progress of work is only printed on the highest level (default).
  The following levels exist:
  • -v0: print only severe and fatal messages.
  • -v1: in addtion to -v0, print also structure violations.
  • -v2: in addtion to -v1, print also errors.
  • -v3: in addtion to -v2, print also implementation limitations that were hit.
  • -v4: in addtion to -v3, print also warnings.
  • -v5 (default): print everything else as well, including remarks and indications on the progress of work.
  See detailed discussion of the messages/verbosity relation in the section on Messages.

• -va: "vertex angles" check the vertex angle, that is, the edge to edge angle, against the explicit value given (e.g., "-va=0.1").
  The angle between two edge's tangents at a common vertex point is calculated and compared against the given value, which is expected to use a degree base. Smaller angles result in a warning (VertexAngle).
  Note 1: More precisely, the angle is the one between the reverse of the first edge's end tangent and the second edge's start tangent
  Note 2: If -va is supplied, -u is implied.
  Note 3: If -u is given, -va=1 is implied if no explicit -va argument is given.

Unsafe Options

No guarantee whatsoever is given that these options yield the results their names promise.

To acknowledge the fact that you are aware of these limitations, it is necessary to supply the additional string "-unsafe" on the command line in order to be able to invoke these options.

• -cp: "create pcurves" create an explicit UV representation (pcurve) for all edges by means of a surface_curve pointing to pcurves and the original 3D curve. The UV curves are b-splines of degree 1. They are, in fact, the representation of what 'lv'`s trimming algorithm computes for the internal representation of faces. Three modes are supported: -cp1 affects only edges on elementary_surfaces and swept_surfaces, -cp2 affects all edges.
  -cp3 can be used to create pcurves selectively. This is done by an additional instance name, e.g. -cp3 4711 or -cp3 #4711. The specified instance can be:
  1. an oriented_edge: pcurve representation is added for this oriented_edge and the other oriented_edges which use the same edge_curve,
  2. an edge_curve: pcurves are created for all oriented_edges that use this edge_curve,
  3. a curve which is either used as edge_curve.edge_geometry, or as a surface_curve.curve_3d which in turn is used as edge_curve.edge_geometry,
  4. an edge_loop or a face_bound, which then creates pcurves for all oriented_edges contained, or
  5. a face_surface, which then creates pcurves for all bounds of that face.
  Several instances can be specified by command repetition, e.g. -cp3 4711 -cp3 5566 -cp3 1966 etc.
  Can be used to help translators that rely heavily on the presence of an explicit UV curve for trimming.

• -e2b: "elementary to b-spline" converts elementary surface types to equivalent NURBS surfaces. Despite this name, currently only supports cylindrical surfaces. Also, only converts surfaces where a face_surface is defined upon. In this case, any pcurves will be removed as the parameterization of the resulting surface is not guaranteed to be invariant.

• -ex: "extrapolate" extrapolate b-spline surfaces that are used to define face_surfaces. The extrapolation is by 2% in each parametric direction of the surface. This is intended to solve potential trim problems in some cases.
  Extension only takes place for parametric directions where the surface is not closed. The option -u has to be specified additionally. Problems may occur if several faces use portions of the same b-spline surface.

• -f2m: "faceted_brep to manifold_surface" conversion of AP203-CC5-type geometry to AP203-CC4-type geometry (-> "-mod.stp" file). Useful for post processors that do not implement faceted breps.
  In case the input faceted breps use the cartesian_points in their poly_loops like vertex_points, i.e., adjacent faces use the same instances, manifold_solid_breps (AP203-CC6-type geometry) are created.
  Caution, causes an approx. 3-fold increase in file size.

• -fb: "filter brep" eliminate all instances of manifold_solid_brep except for those named by -fb "name" arguments (e.g. -fb "inst1" -fb "inst2" ...).
  Useful to extract problematic parts of a big STEP file for further analysis.

• -fc: "filter curve_bounded_surfaces" eliminate all instances of curve_bounded_surface except for those named by -fc "name" arguments (e.g. -fc "inst1" -fc "inst2" ...).
  Useful to extract problematic parts of a big STEP file for further analysis.

• -ff: "filter face" extract face from a solid model for further analysis. All faces given with -ff options are collected in a new manifold_surface_shape_rep. All remaining faces and shape_reps are deleted.
  
  • You may specify an additional '+' after the instance name, e.g. "-ff 1389+". In this case, all faces that are direct neighbours of the indicated face (i.e., which have common edges), are also extracted.
    
  • You may specify the instance name of a surface, instead of a face_surface. This is equivalent to specifying the instance names of all face_surfaces that use this surface.
    
  • Instead, or additionally, you can specify "b+", e.g. "-ff b+". This selects all face_surfaces which are defined on b_spline_surfaces (.face_geometry attribute).
    
  • Likewise, you can specify "b-", e.g. "-ff b-". This selects all face_surfaces that are not defined on b_spline_surfaces. Note that "-ff b+" and "-ff b-" cannot be combined.
    
  Note: Any faces specified which have common edges are put into the same open_shell in the output file. However, it is not checked whether the resulting shell might be a closed_shell.

• -g2m: "geometrically_bounded surface to manifold_surface" conversion of AP203-CC2-type geometry to AP203-CC4-type geometry (-> "-mod.stp" file). Certain surface types, including unbounded surfaces and implicit_outer surfaces are currently unsupported, as well as assemblies.

• -m2g: "manifold_surface to geometrically_bounded surface" conversion of AP203-CC4-type geometry to AP203-CC2-type geometry (-> "-mod.stp" file). Vertex_loops currently unsupported, as well as assemblies.

• -m2s: "mapped_item to shape_representation_relationship" Assemblies that are encoded using the so-called "mapped_item" approach will be replaced by the more common "shape_representation_relationship" approach.
  Note 1: One of the reasons why this is an "unsafe" option is that it will attempt to replace any mapped_item in the product, regardless of the context it was used for.
  Note 2: If the mapped_item's mapping_target is a cartesian_transformation_operator, it will be replaced by an axis2_placement_3d. This can be only successful if the cartesian_transformation_operator does not define a mirroring or scaling transformation.

• -ncs: "normalize coordinate system" after performing an -as3 (create explicit part for assembly if present, see above) this option will compute the bounding box of all vertex_points in the part. The geometry will then be shifted so that the center of this bounding box is the origin. The purpose is to improve translation results for post processors where the underlying CAD system has strong limitations on the maximum coordinate value that is supported, if the input model is located far away from the origin. If the input does not contain vertex_points, the operation is not performed and no modified file gets written.

• -rh: "restructure hybrid models" restructures the input as follows:
  If a part is not a hybrid model, i.e., it contains only geometry of one type (solid, manifold surfaces, geometrically_bounded surfaces, or wireframe), it guarantees that the part is described by a single, specialized shape_representation subtype.
  Otherwise, in case of a hybrid model, the output is controlled by the -rh option as follows:

  • -rh1: Creates multiple specialized shape_reps that are linked to the same product. This works only if the input is not an assembly.

  • -rh2: Creates specialized shape_reps that are linked via "shape_representation_relationship" to a plain shape_rep that is linked to the product ("STEPnet approach for mixed models")

  • -rh3: Creates a plain shape_representation for all geometry ("AP214 hybrid model approach")

  • -rh4: Eliminates all non-solid geometry and represents the solids in an advanced_brep_shape_rep

  • -rh5: Eliminates all non-manifold_surface geometry and represents the faces in a manifold_surface_shape_rep

  This option can be used to reduce the hybrid model cases, and to restructure the output for some post processors' requirements. Compare to the option -as (see above). In opposition to -as, assemblies will remain assemblies because we work on a part- per-part basis. However this will not work for assemblies if the input is as described for "-rh1".

• -rmax: "convert circle to line" in combination with -u -ns, 'lv' checks if a circle used to define the geometry of an edge_curve has a radius that exceeds the value given with this option, e.g. "-rmax=10000". In this case, the circle will be replaced by a line if this is possible for the given distance_accuracy value. If the circle cannot be replaced by a line, it will be replaced by a linear b-spline curve with 10 control points (regardless of whether the deviation is then within the distance accuracy or not).
  Note: This option is deactivated if -u3 is given.

• -rs: "rotate seam" attempt to rotate periodic surfaces (cylinders, cones, spheres, and toroidal_surfs) so that their seam, and, in the case of a sphere, their pole, does not interfere with faces. Two different strategies are supported (-rs1, -rs2). If an additional '+' is given (e.g. "-rs1+"), then in some cases toroidal_surfaces will be replaced by equivalent surface_of_revolution instances in order to increase the potential for repair.
  Note: Some modellers have restrictions in respect to faces on periodic surfaces. This option can improve the results of postprocessing the STEP file with their translators. Implementation is restricted to faces.

• -scb: "set colors for breps" removes any color and layer information that is present in the input, and will assign each manifold_solid_brep an unique layer and one color of a set of eight.

• -sp: "split assembly" works on an input file that contains assembly information. 'lv' will create a subdirectory with the name of the STEP input file. In this subdirectory, a STEP file with the name of the input will be written that contains the assembly placement information. The original geometry of each shape will be represented by a single "anchor" point.
  Additionally, STEP files are written for each single part contained in the assembly. These STEP files will have the name of the corresponding product.id attribute. The purpose is to break up assembly files for target systems that have size limitations or do not support assemblies at all (see also: -as option).
  Note: Will not work on non-assembly input, or if the product.id's are not unique.

• -u: In combination with -unsafe, the -u option will enable some checks that are not reliable in all cases, but rather hint to situations that might be troublesome, requiring the user's attention in order to decide.
  This mode is used by default if 'lv' is used interactively, i.e., repairing activities are not enabled and the option -ns is not provided)
  In case the combination -u -unsafe is used for batch operation (i.e., repair is enabled or the option -ns is provided), this will make 'lv' try some more hazardous repairs on the given product.