aleutgeb / steptoxsection

The program STEPToXSection is a command line utility to export the contour of a planar cross section of solids contained in STEP files. It supports surface offsetting of the input geometry and in-plane curve offsetting. The in-plane base contour can also result from the orthogonal projection of geometries (silhouette) onto the plane within a specified maximum plane distance.

STEPToXSection

Description

The program STEPToXSection is a command line utility to export the contour of a planar cross section of solids contained in STEP files. It supports surface offsetting of the input geometry and in-plane curve offsetting. The in-plane base contour can also result from the orthogonal projection of geometries (silhouette) onto the plane within a specified maximum plane distance. The contour is a list of line segments. The supported output file formats are ply (edges, polygons, or triangles) and xyz. In the case of xyz, two consecutive vertices belong to the same edge. A popular viewer for the different file types is MeshLab (https://www.meshlab.net). STEPToXSection is based on OpenCASCADE (https://www.opencascade.com). The program uses cxxops (https://github.com/jarro2783/cxxopts) for parsing the command line.

Requirements

• CMake installation (https://cmake.org)
• Visual Studio C++ installation (https://visualstudio.microsoft.com)
• OpenCASCADE installation (https://old.opencascade.com/content/latest-release, download needs registration)

Usage

Listing the contents (solids) of a STEP file: STEPToXSection -c -i <step file>

Computing the planar cross section contour of the overall file content (solids):

STEPToXSection -i <step file> -o <output file> -d <deflection> -p <plane>

The parameter <deflection> controls the resolution of the approximation with line segments.

Computing the planar cross section contour of selected solids of the file:

STEPToXSection -i <step file> -o <output file> -d <deflection> -p <plane> -s <solid1>,<solid2>,<...>

In order to change the default output format ply (edges) the command line argument -f xyzhas to be specified.

Following the help text from the command line:

STEPToXSection.exe
Extracts a contour of the planar cross section of solids contained in STEP files. The programm supports surface offsetting of the input geometry and in-plane curve offsetting. The in-plane base contour can also result from the orthogonal projection of geometries (silhouette) onto the plane within a specified maximum plane distance.
Usage:
  STEPToXSection [OPTION...]

  -i, --in arg              Input file
  -o, --out arg             Output file
  -f, --format arg          Output file format (xyz, ply_edges, ply_polygons,
                            or ply_triangles) (default: ply_edges)
  -c, --content             List content (solids)
  -s, --select arg          Select solids by name or index (comma seperated
                            list, index starts with 1)
  -d, --deflection arg      Chordal tolerance used during discretization
  -p, --plane arg           Single plane (a,b,c,d) or parallel planes
                            (a,b,c,d_start,d_end,d_count), in which a*x + b*y + c*z +
                            d = 0
  -1, --surface_offset arg  Single offset (value) or range offset
                            (start,end,count) for surface offsetting of input geometry
  -2, --curve_offset arg    Single offset (value) or range offset
                            (start,end,count) for in-plane curve offsetting
  -n, --projection arg      Orthogonal projection of geometries with
                            specified maximum plane distance, in which the silhouette
                            of the projected geometries represents the
                            in-plane base contour
  -h, --help                Print usage

Examples

Examples spheres.stp and bone_pocket.stp are from the examples directory.

Examples Spheres

Solids

Planar cross section
STEPToXSection.exe -i spheres.stp -o out.ply -f ply_edges -d 0.01 -p 1.0,0.0,0.0,0.0

Planar cross sections
STEPToXSection.exe -i spheres.stp -o out.ply -f ply_edges -d 0.01 -p 1.0,0.0,0.0,-4.0,4.0,6

Positive in-plane offset curves
STEPToXSection.exe -i spheres.stp -o out.ply -f ply_edges -d 0.01 -p 1.0,0.0,0.0,0.0 -2 0.0,10.0,10

Negative in-plane offset curves
STEPToXSection.exe -i spheres.stp -o out.ply -f ply_edges -d 0.01 -p 1.0,0.0,0.0,0.0 -2 0.0,-4.9,5

Example Bone Pocket

Solid

Planar cross section
STEPToXSection.exe -i Bone_Pocket.stp -o out.ply -f ply_edges -d 0.01 -p 0.0,0.0,1.0,0.0

Planar cross sections
STEPToXSection.exe -i Bone_Pocket.stp -o out.ply -f ply_edges -d 0.01 -p 0.0,0.0,1.0,-4.0,4.0,5

Positive in-plane offset curves
STEPToXSection.exe -i Bone_Pocket.stp -o out.ply -f ply_edges -d 0.01 -p 0.0,0.0,1.0,0.0 -2 0.0,4.0,5

Negative in-plane offset curves
STEPToXSection.exe -i Bone_Pocket.stp -o out.ply -f ply_edges -d 0.01 -p 0.0,0.0,1.0,0.0 -2 0.0,-2.0,3

Silhouette of projected geometry within plane distance
STEPToXSection.exe -i Bone_Pocket.stp -o out.ply -f ply_edges -d 0.01 -p 0.0,0.0,1.0,0.0 -n 3.0

Silhouettes of projected geometry within plane distance
STEPToXSection.exe -i Bone_Pocket.stp -o out.ply -f ply_edges -d 0.01 -p 0.0,0.0,1.0,2.5,0.0,6 -n 1.0

Planar cross-sections using positive surface offset
STEPToXSection.exe -i Bone_Pocket.stp -o out.ply -f ply_edges -d 0.01 -p 0.0,0.0,1.0,2.5,0.0,6 -1 1.5

Remarks

This code has been tested with an OpenCASCADE 7.5.0 prebuilt binary (opencascade-7.5.0-vc14-64.exe) on Windows, as well as OpenCASCADE system packages on openSUSE Linux. With changes in the configuration section in the CMakeLists.txt file the build should also work with other OpenCASCADE versions.

steptoxsection's Issues

Slice solid from offset surfaces

Hello,
Is it possible with your lib to slice the input solid with a 3d base surface (not a plane), and get the resulting surface of solid (and contour)? And then repeat with another surface, offset from the base one ?
Thank you

Slicing KO with shape surface

Hello,

I tried to slice a STEP surface (gyroid) using that way:
STEPToXSection.exe -i %stepFile% -o GyroSeul.ply -f xyz -d 0.01 -p 1.0,0.0,0.0,0
but the output ply file is empty.

STEP file:
gyroide surf seule.zip

merge with STEPToMesh (and STEPToPoints?)

For easier deployment (especially when linking statically) and to reduce code duplication and maintenance efforts between the STEP processing tools, it could make sense to merge them into a single project, producing a single binary which can be invoked in several modes, e.g. similar to how the command line clients of git or svn work.

Listing the contents of a STEP file (i.e. -c) could then be a dedicated mode because it is shared between all other processing modes.

The code for reading a STEP file, for parts selection and maybe specifying the working unit (see aleutgeb/STEPToMesh#4) could be shared.

Issues with polygon results of multi-slicing

Hello,

when calling your 'multiple slicing' on the 'bone' test case (with Polygon output type), the final results (in the output .ply file) does not look good: the triangles shared a same vertex/node, leading to triangles edges crossing the 'bone" slice boundary (see image).
I expected to have a kind of delaunay triangulation inside the slice boundary.