Build132d Shape History

A tool to manage and visualize the modification history of Build123D objects.

Installation

This package is published on Pypi:

pip install bd_shape_history

Usage

Assuming a simple part created in 3 steps:

box = _.Box(3, 3, 1)
cbox = _.chamfer(box.edges()[0], 0.5)
cboxh = cbox - _.Cylinder(0.75, 1)

We can build the history with:

hm = ShapeHistory.from_globals()

And then display it diff() (here with VScode OCP CAD viewer):

ov.set_defaults(render_edges=False)
ov.show(*hm.diff(), names=hm.labels())

This shows a visual diff between each step:

Notice how the object is colored:

• new faces and edges are green and light green;
• unchanged faces and edges are gray and black;
• modified faces and edges are dark green and olive

See the examples folder for more details.

Command line interface

You can compare two files and export the diff as an image using the ocp_diff script. For instance:

ocp_diff ./examples/a.py:box ./examples/b.py:box img.png

How does it work

ShapeHistory compares the hash of faces, edges and vertices between each steps:

• a face or edge whose hash is found on the previous step is considered unmodified;
• a face whose all edges are not found in the previous step is considered added (and same for edge / vertices);
• otherwise the face or edge is considered modified.