OCP CAD Viewer for VS Code

OCP CAD Viewer for VS Code is an extension to show CadQuery and build123d objects in VS Code via the three-cad-viewer viewer component.

Installation

Prerequisites

• A fairly recent version of Microsoft VS Code, e.g. 1.85.0 or newer
• The Python extension installed in VS Code
• Necessary tools:
  • python and pip available in the Python enviroment that will be used for CAD development
  • The command git needs to be available
  • On a Silicon Apple computer the command mamba needs to be available. You might want to consider using Mambaforge.

Notes:

• To use OCP CAD Viewer, start VS Code from the commandline in the Python environment you want to use or select the right Python interpreter in VS Code first. OCP CAD Viewer depends on VS Code using the right Python interpreter (i.e. mamba / conda / pyenv / poetry / ... environment).
• For VSCodium, the extension is not available in the VS code market place. You need to download the the vsix file from the release folder and install it manually.
• Currently, on a Silicon Mac (ARM CPU), OCP and CadQuery can only be installed via mamba, see 3. below.

Installation

1. Open the VS Code Marketplace, and search and install OCP CAD Viewer 2.6.1.

   Afterwards the OCP viewer is available in the VS Code sidebar:

   

2. Clicking on it shows the OCP CAD Viewer UI with the viewer manager and the library manager:

   

   You have 3 options:

   • Prepare OCP CAD Viewer for working with build123d: Presse the Quickstart build123d button.

     This will install OCP, build123d, ipykernel (_jupyterclient), _ocptessellate and _ocpvscode via pip (except for Apple Silicon machines that require mamba and will also install cadquery)

     

   • Prepare OCP CAD Viewer for working with CadQuery: Presse the Quickstart CadQuery button.

     This will install OCP, CadQuery, ipykernel (_jupyterclient), _ocptessellate and _ocpvscode via pip (except for Apple Silicon machines that require mamba)

     

   • Ignore the quick starts and use the "Library Manager" to install the libraries. Doing so, OCP CAD Viewer let's you select whether to use pip, mamba, conda or poetry. Install the needed library by pressing the down-arrow behind the library name (hover over the library name to see the button) in the "Library Manager" section of the OCP CAD Viewer sidebar. For more details, see here

   The Quickstarts will also

   • (optionally) install the the Jupyter extension for VS Code from Microsoft
   • start the OCP viewer
   • create a demo file in a temporary folder to quickly see a simple usage example

3. On Silicon Macs (ARM CPU)

   • Install Miniforge
     • Option 1: Download and install from the Miniforge github page
     • Option 2: Use homebrew: brew install miniforge
   • Initialize your shell for mamba: mamba init $(basename "$SHELL")
   • Create an environment, e.g named code_cad with Python 3.10: mamba create -n code_cad python=3.10
   • Activate the environment: mamba activate code_cad
   • Start VS Code from your working folder: code .
   • Install the Python extension in VS Code
   • Continue with 1. above

Notes:

• Do not use the OCP CAD Viewer logo to verify your OCP CAD Viewer settings! The logo overwrites all your settings in VS Code with its own settings to always look the same on each instance. Use a simple own model for checking your conmfiguration

• If you run into issues, see Troubleshooting

Usage

Running code using Jupyter

• Start the OCP CAD Viewer by pressing the box-arrow button in the "Viewer Manager" section of the OCP CAD Viewer sidebar (hover over the ocp_vscode entry to see the button).
• Import ocp_vscode and the CAD library by using the paste button behing the library names in the "Viewer Manager" section
• Use the usual Run menu to run the code

Debugging code with visual debugging

After each step, the debugger checks all variables in locals() for being CAD objects and displays them with their variable name. Note:

• Check that OCP:on is visible in the status bar
• It also shows planes, locations and axis, so name your contexts
• It remembers camera position and unselected variables in the tree
• during debugging, show and show_object are disabled. They interfere with the visual debugging

Library Manager

You can also use "Library Manager" in the OCP CAD Viewer sidebar to manage the Python libraries for build123d, cadquery, ipython and _ocptessellate (Presse the down-arrow when hovering over a library name to install/upgrade it)

Extra topics

• Quickstart experience on Windows
• Use Jupyter to execute code
• Debug code with visual debugging
• Measure mode
• Use the show command
• Use the show_object command
• Use the set_viewer_config command
• Download examples for build123d or cadquery
• Use the build123d snippets

Standalone mode

Standalone mode allows to use OCP CAD Viewer without VS Code: python -m ocp_vscode. This will start a Flask server and the viewer can be reached under http://127.0.0.1/viewer. All client side feature of the VS Code variant (i.e. show* features) should be available (including measurement mode) except visual debugging (see above) which relies on VS Code.

Use python -m ocp_vscode --help to understand the command line args:

Usage: python -m ocp_vscode [OPTIONS]

Options:
  --create_configfile            Create the configlie .ocpvscode_standalone in
                                 the home directory
  --host TEXT                    The host to start OCP CAD with
  --port INTEGER                 The port to start OCP CAD with
  --debug                        Show debugging information
  --timeit                       Show timing information
  --tree_width TEXT              OCP CAD Viewer navigation tree width
                                 (default: 240)
  --no_glass                     Do not use glass mode with transparent
                                 navigation tree
  --theme TEXT                   Use theme 'light' or 'dark' (default:
                                 'light')
  --no_tools                     Do not show toolbar
  --tree_width INTEGER           Width of the CAD navigation tree (default:
                                 240)
  --control TEXT                 Use control mode 'orbit'or 'trackball'
  --up TEXT                      Provides up direction, 'Z', 'Y' or 'L'
                                 (legacy) (default: Z)
  --rotate_speed INTEGER         Rotation speed (default: 1)
  --zoom_speed INTEGER           Zoom speed (default: 1)
  --pan_speed INTEGER            Pan speed (default: 1)
  --axes                         Show axes
  --axes0                        Show axes at the origin (0, 0, 0)
  --black_edges                  Show edges in black
  --grid_xy                      Show grid on XY plane
  --grid_yz                      Show grid on YZ plane
  --grid_xz                      Show grid on XZ plane
  --center_grid                  Show grid planes crossing at center of object
                                 or global origin(default: False)
  --collapse INTEGER             leaves: collapse all leaf nodes, all:
                                 collapse all nodes, none: expand all nodes,
                                 root: expand root only (default: leaves)
  --perspective                  Use perspective camera
  --ticks INTEGER                Default number of ticks (default: 10)
  --transparent                  Show objects transparent
  --default_opacity FLOAT        Default opacity for transparent objects
                                 (default: 0.5)
  --explode                      Turn explode mode on
  --angular_tolerance FLOAT      Angular tolerance for tessellation algorithm
                                 (default: 0.2)
  --deviation FLOAT              Deviation of for tessellation algorithm
                                 (default: 0.1)
  --default_color TEXT           Default shape color, CSS3 color names are
                                 allowed (default: #e8b024)
  --default_edgecolor TEXT       Default color of the edges of shapes, CSS3
                                 color names are allowed (default: #707070)
  --default_thickedgecolor TEXT  Default color of lines, CSS3 color names are
                                 allowed (default: MediumOrchid)
  --default_facecolor TEXT       Default color of faces, CSS3 color names are
                                 allowed (default: Violet)
  --default_vertexcolor TEXT     Default color of vertices, CSS3 color names
                                 are allowed (default: MediumOrchid)
  --ambient_intensity INTEGER    Intensity of ambient light (default: 1.00)
  --direct_intensity FLOAT       Intensity of direct light (default: 1.10)
  --metalness FLOAT              Metalness property of material (default:
                                 0.30)
  --roughness FLOAT              Roughness property of material (default:
                                 0.65)
  --help                         Show this message and exit.

Best practices

• Use the Jupyter extension for a more interactive experience. This allows to have one cell (separated by # %%) at the beginning to import all libraries

  # %%
  from build123d import *
  from ocp_vscode import *
  
  # %%
  b = Box(1,2,3)
  show(b)
  # %%

  and then only execute the code in the cell you are currently working on repeatedly.

• The config system of OCP CAD Viewer

  There are 3 levels:

  • Workspace configuration (part of the VS Code settings, you can access them e.g. via the gear symbol in OCP CAD Viewer's "Viewer Manager" when you hover over the label "VIEWER MANAGER" to see the button)
  • Defaults set with the command set_defaults per Python file
  • Parameters in show or show_object per command

  set_defaults overrides the Workspace settings and parameters in show and show_config override the other two.

  Note that not all parameters are available in the global Workspace config, since they don't make sense globally (e.g. helper_scale which depends on the size of the boundary box of the currently shown object)

  A common setup would be

  # %%
  from build123d import *
  import cadquery as cq
  
  from ocp_vscode import *
  set_port(3939)
  
  set_defaults(reset_camera=False, helper_scale=5)
  
  # %%
  ...

  Explanation

  • The first block imports build123d and CadQuery (omit what you are not interested in).
  • The second block imports all commands for OCP CAD Viewer. set_port is only needed when you have more than one viewer open and can be omitted for the first viewer)
  • The third block as an example sets helper_scale and reset_camera as defaults. Then every show_object or show command will respect it as the default

• Debugging build123d with show_all and the visual debugger

  • If you name your contexts (including Location contexts), the visual debugger will show the CAD objects assigned to the context.

  • Use show_all to show all cad objects in the current scope (locals()) of the Python interpreter (btw. the visual debugger uses show_all at each step)

  # %%
  from build123d import *
  set_defaults(helper_scale=1, transparent=True)
  
  with BuildPart() as bp:
      with PolarLocations(3,8) as locs:
          Box(1,1,1)
  
  show_all()
  # %%

  

• Keep camera orientation of an object with reset_camera

  Sometimes it is helpful to keep the orientation of an object across code changes. This is what reset_camera does:

  • reset_camera=Camera.Center will keep position and rotation, but ignore panning. This means the new object will be repositioned to the center (most robust approach)
  • reset_camera=Camera.KEEP will keep position, rotation and panning. However, panning can be problematic. When the next object to be shown is much larger or smaller and the object before was panned, it can happen that nothing is visible (the new object at the pan location is outside of the viewer frustum). OCP CAD Viewer checks whether the bounding box of an object is 2x smaller or larger than the one of the last shown object. If so, it falls back to Camera.CENTER. A notification is written to the OCP CAD Viewer output panel.
  • reset_camera=Camera.RESET will ensure that position, rotation and panning will be reset to the initial default

Development

Testing:

Native tessellator can be set via NATIVE_TESSELLATOR=1and Python tessellator via NATIVE_TESSELLATOR=0.

When OCP_VSCODE_PYTEST=1 is set, show will not send the tessellated results to the viewer, but return it to the caller for inspection.

A full test cycle consist of:

NATIVE_TESSELLATOR=0 OCP_VSCODE_PYTEST=1 pytest -v -s pytests/
NATIVE_TESSELLATOR=1 OCP_VSCODE_PYTEST=1 pytest -v -s pytests/

Troubleshooting

• Generic ("it doesn't work")

  1) Confirm that VS Code extension and ocp_vscode have the same version. This can be seen in the OCP CAD Viewer UI. Or alternatively in the Output panel of VS Code:

    [19:56:07.114} INFO  ] ocp_vscode library version 2.6.1 matches extension version 2.6.1

  2) Test whether the standalone viewer works, see Standalone mode (to eliminate VS Code issues) 3) Open a work folder and not a Python file (to ensure we do not get in Python path problems) 4) Check the Output panel. Search for:

  • PythonPath: 'aaa/bbb/python' => right Python environment?
  • Server started on port xxxx (or so) => right port? default is 3939
  • Starting Websocket server => should not be followed by an error
  • OCP Cad Viewer port: xxxx, folder: yyyy zzzz => yyyy should be the right working folder? 5) If all looks fine until now, then toggle Developer tools in VS Code and check browser console. Often we see a WebGL error for the browser of VS Code used for the viewer.

• CAD Models almost always are invisible in the OCP viewer window

  three-cad-viewer.esm.js:20276 THREE.WebGLProgram: Shader Error 0 - VALIDATE_STATUS false
  
  Material Name:
  Material Type: LineBasicMaterial
  
  Program Info Log: Program binary could not be loaded. Binary is not compatible with current driver/hardware combination. Driver build date Mar 19 2024. Please check build information of source that generated the binary.
  Location of variable pc_fragColor conflicts with another variable.

  VS Code internal browser that renders the viewer component uses a cache for code and other artifacts. This includes WebGL artefacts like compiled shaders. It can happen that e.g. due to a graphic driver update the compiled version in the cache does not fit to the new driver. Then this error message appears.

  Solution: Delete the VS Code browser cache on Linux (go to the section for your operating system)

Changes

v2.6.1

Fixes:

• Standalone viewer can listen to other IP addresses of the machine than 127.0.0.1
• show now uses port 3939 as default when no port could be detected and a service listens to 3939
• Fixed a bug in ocp-tessellate for cadquery wires (#116)
• Fixed a bug in backend for measures that prevented faces being inspected (#115)
• Fixed a bug that shifted the orientation too high for the logo screen

v2.6.0

New features

• Standalone mode without VS Code: python -m ocp_vscode. This will start a Flask server and the viewer can be reached under http://127.0.0.1/viewer.

Fixes:

• Fix that show_all doesn't ignore _123 and similar variable names