Backstory: We are a scouting family. I had a new scout join our troop who is in a wheelchair. We meet in the historic building at the church who sponsors us and that old building was built at a time when handicap access wasn’t a thing. I decided to test out my ability to put the whole process together and make some ramps to get him from the parking area up into the main front door.
Step 1: I used a Leia MS60 to 3D laser scan the whole area so that I could find the best location for each ramp in AutoCAD Civil 3D. (I’m a civil engineer and I have access to nice stuff for this kind of thing). I brought the data in and cut some cross sections in the most friendly locations.
Step 2: Export the cross sections as DXF then bring them into Fusion360 and sketch up some geometry for the ramp, extrude it, make the supports to fill the rest of the triangle. Since he has a power chair that has some heft, I made a double support about 5-inches center to center. I used a parameter based design and made pockets and tabs that were thickness/2 ** NOTE: In the final glue up, I thought that the whole thing might rack under load, so I added 2x4 blocks between the tabs on each set of supports.
Step 3: I setup the tool paths to cut the supports and the main ramps separate. I used pocket cuts, some 3d adaptive clearing, then 3d parallel cuts, and profile cuts.
edit: The parallel cuts came out really nice. Because I started with high-resolution laser scan data, I made the edges to fit right up against the curb in the parking area and the transom at the door.
Step 4: Assembly - glue time. **Note: I originally intended it to be put together and taken apart, then I remembered that I was dealing with 11-17 yr olds every week, and maybe they should just be glued up so we don’t misplace pieces. Plus it is much stronger glued up with the extra blocks.
Step 5: Test fit = Success!
Seems that it all fits great!
I added some cautionary orange paint, that also helps us put the ramp back in the correct location. The curb seems to have been hand worked in this area when it was poured, and the height varies quite drastically so the paint will help get it placed where I designed it to go.