Using Miraco to design a part that fits to a complex object
Problem
The controller for my drone (DJI Mini 4 Pro) only has mounts for a neck-strap at the rear.
This means it flops forward when not supported. I would like a way to hold it at it’s center of mass.
There are trays that mount to the controller but they increase it’s bulk quite considerably. Ideally I want something that mounts a strap here:
Scanning
In order to create the part, we first need to create a scan of the DJI RC2 controller. It doesn’t need to be mega-detailed but we might as well show off Miraco while we’re doing it:
Getting it in to CAD
There are several ways we can get this model in to CAD. We could re-draw it from section sketches like I’ve shown before but for this project, we’ll use a different way.
Triangles to quads
I want to create a T-spline model of the controller in Fusion360. Unfortunately, the mesh to T-spline converter can only deal with quad meshes and the output of Revoscan (and all other scanning tools really) is triangles. We can covert the model to quads using a nice, free tool called Instant Meshes: GitHub - wjakob/instant-meshes: Interactive field-aligned mesh generator
Let’s load up our scan; click Open Mesh:
Our mesh is loaded and ready for conversion:
At the moment, our target vertex count is way too high at 100k. Fusion360 will have a fit. We want that around the 10k mark ideally. Move the slider to 10k:
Next, hit Solve under Orientation Field
Our mesh will have lots of pretty colours on it now.
Then, hit Solve under Position Field
And now our mesh is all squares:
Hit Export and choose Pure quad mesh (this will ensure that all the facets are quads and that no triangles remain.
Finally, Extract Mesh
And Save
Now, over the Fusion360:
Create a new project, import your quad-mesh and orientate it so that it’s aligned with X, Y, and Z.
Next, under the surface tab, select New Form
Then hit Convert
We want Quad-mesh to T-Spline
Hit OK, and Fusion will chew on it for a while, then hit Finish Form
We now have a defined solid in Fusion that we can do all sorts of things with:
As you can see, we can cut it up just like a normal solid
OK, back together we want to make a copy of it
The new object, we want to scale it to make it bigger. I want something that will fit around the controller but follow the controllers lines. Let’s make it 1.1x bigger. Make sure to scale from the origin rather than a corner.
Now, let’s cut it up and make the rough model that we want:
Now we have our rough model, let’s put it over the 1.0 scaled original model and then use that model as a tool to cut out from our new part:
We end up with this, ready for an attachment to be added:
A quick bit of CAD and we have our part:
This is what it looks like rendered in Fusion:
Let’s print it and see how it fits:
Like a glove:
