Week 2. Computer Aided Design
Let's learn some CAD...
Summery
We’re going to select and evaluate 2d and 3d software this week.
2d packages will include Adobe Fresco (iPad), Sketchbook Pro (iPad) and Adobe Illustrator (Mac or PC)
3d packages will include, Autodesk Fusion, Onshape, Rhino3d and Grasshopper
I will also demonstrate image and video compression
I will model some parts for potential final projects (I still haven’t decided on the final project, but I think it will be a hexapod/Stewart platform).
We will start with a basic modeling of a solar panel system for the mobile fab lab. I scanned the van using photogrammetry, and you can see this process documented in later weeks. An .FBX file of the scanned van was imported into Fusion and aligned to the origin. A basic frame for the panels was modeled.
Onshape was used to model a solar panel found online that could be suitable for this application. This was done to explore software options. The file was exported from Onshape and imported into an Autodesk Fusion assembly.
We will also look at modeling and animating the hexapod or Stewart platform in Rhino and Grasshopper.
Autodesk Fusion
Created new project in the data panel called Technology Van
I then uploaded the 3d scan file of the van in .FBX format and opened this document.
The scanned part needs to be aligned to the origin. Use the move command (type "m" on the keyboard for a shortcut) and select the mesh body to move.
For this part, I will orient the mesh so the origin sits at the center of the roof.
There is probably a more accurate way to do this, But I maneuver the part by eye. I use screen edges to align the van – just make sure the camera is set to orthographic and you are using the cube in the top right to set the view perpendicular (i.e., Top or Front).
You can press the dot to rotate the part. It will likely jump to 2.5 degrees minimum. To move it in smaller increments, you will need to manually type the angle in the pop-up dialogue box. In this case, I neede to move 1 degree to get the front bumper aligned horizontally.
Once happy with the alignment, we need to start capturing design history. Right-click the part at the top of the browser; "Capture Design History" is at the bottom. This must be done for files that have been imported if you want to be able to edit features created.
We also need to change the document units. This can be done in document settings by clicking the little arrow to access the drop-down. Set it to millimetres (or your preferred unit system).
We are now ready to start modelling our part. I start by referencing the side panels of the van where it will be possible to mount support rails. To do this we switch to the “mesh tab” use the “create mesh selection tool” select a plane that intersects the geometry and move to the desired location with the arrow.
Click the little arrow beside the sketch folder in the browser, find the sketch just created, right click and select edit sketch
We can now match sketch geometry using Fit Curves to Mesh Selection. This can be found by clicking the Create drop-down in the sketch toolbar.
I used the fit spline tool and selected two points on the orange mesh intersection sketch in the area where I wanted to model a sketch that closely matched the contour of the van panel.
At this point I identified potential solar panels that would fit the frame meet the technical specifications required. The panel identified below on initial inspection seemed to meet the requirements in terms of dimensions and weight. I took a screenshot of the plan view image with dimensions. I would be able to bring this into the CAD package to trace the panel and to model it in CAD accurately.
Onshape
I decided to use Onshape to model this part. Below are the steps taken to model the part.
Rhino and Grasshopper
Learning Outcomes
Experienced using Fusion, Onshape and Rhino – of the 3 packages tested I prefer Fusion, time didn’t allow me to test other software however I would like to try more modelling in Blender – perhaps in the future.