Merge pull request #211 from orionrobots/2025-07-05-blog

Create 05-freecad-notes.md

Author: dannystaple

.eleventy.js

@@ -45,6 +45,7 @@ module.exports = function (eleventyConfig) {
     install_media_objects(eleventyConfig);
 
     //copy through assets
+    eleventyConfig.setServerPassthroughCopyBehavior("passthrough");
     eleventyConfig.addPassthroughCopy("admin");
     eleventyConfig.addPassthroughCopy("assets");
     eleventyConfig.addPassthroughCopy("dist");

.markdown-link-check.json

@@ -0,0 +1,6 @@
+{
+    "projectBaseUrl": "https://orionrobots.co.uk/",
+    "retryOn429": true,
+    "retryCount": 5,
+    "aliveStatusCodes": [ 200, 203 ]
+}

content/2025/07-05-freecad/05-freecad-notes.md

@@ -0,0 +1,73 @@
+---
+title: FreeCAD notes - working in the new assembly workbench
+tags: [FreeCAD, 3D CAD]
+date: 2025-07-05
+thumbnail: content/2025/07-05-freecad/knolling-freecad-assembly.png
+---
+I've been slowly getting my head around the new (FreeCAD 1.0) assembly workbench, and using it to create exploded diagrams for my upcoming book, Learn Robotics Programming Third Edition. 
+hese are some notes and observations while doing so.
+
+I'd previously used the exploded assembly workbnehc and others, but the new assembly workbench is rather good.
+It uses joint/constraint based assembly with a resolver.
+
+A critical note in FreeCAD - save your work very often, it does crash or hang sometimes.
+
+## Knolling before the assembly
+
+When you make the assembly in FreeCAD, you insert parts from your open documents into it.
+Initially they all are inserted at the origin (0, 0, 0).
+What I like to do is drag them out as I place them.
+
+For the photos I use in my books, I lay parts that I would assemble on a workbench (trying to find a good white surface for photos), so they can all be clearly seen and the quantity.
+This technique is known as knolling, and creates quite pleasing assembly instructions.
+
+![Using Knolling for a Raspberry Pi HAT assembly](/2025/07-05-freecad/knolling-raspberrry-pi-hat-assembly.png)
+
+The same technique is handy when making FreeCAD assemblies, making the parts easier to assemble into place with joints/constraints afterwards:
+
+![Knolling an asssembly in FreeCAD](/2025/07-05-freecad/knolling-freecad-assembly.png)
+
+You can do this by using the drag handles on the parts when you've added them.
+If you lose the drag handles, while still in the add parts mode, you double click a part to get them back.
+
+## Trying the Parts workbench
+
+For some reason, in FreeCAD, I'd largely been using the Part Design workbench, perhaps because it is hte defualtr you start with.
+I've been using the Part workbench instead for a week, after seeing a video on the subject.
+Much of my workflow - draw sketches, extrude them and draw more, is the same.
+
+However, operations like being able to mirror, cut parts and use boolean combinations (union, subtraction) are more accessible in this workbench.
+I'll keep going and see where I get to.
+
+I use boolean operations a lot in my Inkscape 2D drawing workflow, to construct shapes, so it is nice to have them in FreeCAD too.
+
+## Creating exploded diagrams
+
+You can explode an assembly by selecting an assembly in the workbench, and pressing "E", or finding Exploded Assembly in the menu.
+
+My technique is to CTRL-select groups of bolts together and lift them out of the assembly, just remember to give clearance for other parts to come off too.
+
+![Exploded assembly in FreeCAD](/2025/07-05-freecad/freecad-exploded-assembly.png)
+
+You can then take these into a Technical drawing, using the TechDraw workbench.
+Create your page, then select the exploded asssembly in the model tree.
+Then use the Insert View button to add it to the page.
+The FrontTopLeft view is a good one to use.
+
+![FreeCAD exploded assembly in TechDraw](/2025/07-05-freecad/freecad-exploded-assembly-in-techdraw.png)
+
+You'll note an odd thing with surfaces being filled in between the exploded assembly lines, also that the movement lines aren't dashed.
+This is still an area with active development, so hopefully these will be fixed in future releases.
+The work around for the filled in surfaces is to select the view, and in the property editor, select the "view" tab and set the "Face Color" to white.
+For the dashes, it is a little painstaking, but you need to select the lines you want to change, then the "Change appearance of lines" tool, and then set the line style to "Stitch" in the property editor.
+
+Also beware that in the TechDraw workbench, the undo system doesn't yet work.
+
+## What am I building?
+
+If you want to see these diagrams in the context of the robot I'm building with them, this will be in my upcoming book, Learn Robotics Programming Third Edition.
+
+The reader is taken through building and programming a Raspberry Pi based robot rover platform, designed for explorign sensors and algorithms at relatively low cost.
+
+The robot code has web pages to interact with the robot and view its data, using technologies like Python and MQTT.
+There's AI based face detection, localisation algorithms and more.