I made these Dinos from plans that I found around the internet. I cleaned up and modified the files to cut on 1/8 plywood. I’ve included the SVG and DXF files for all of the Dinos.
I Made the tolerances for a tight fit. I found a nice hammer to tap the pieces in place here http://cartonus.com/hammer/
If you like these, you might like to try the anatomically correct dinos on makecnc.com. They’re not free, but the models are a lot better than the basic ones you find on the web.
To work with 1/4 plywood, scale up the pattern. Then cut a couple of smaller pieces and check the fit.
You could also measure the thickness of the plywood, then scale the pattern so the slots match the measurement.