Rendering a photorealistic image of a BikeCAD model using FreeCAD and CADRays.

To obtain a photorealistic rendering of your BikeCAD model, first export the model to FreeCAD. Import the resulting Python script into FreeCAD and click the green execute button to obtain a 3D model of your design. In this example we&generate our photorealistic image using the ray tracing program CADRays by OpenCascade. To prepare for this, we&need to export our model as a collection of STEP files. On the left side of the FreeCAD interface, we&see the Tree View which lists each of the elements that make up our design. We&hold down the ctrl key and select all of the elements representing the frame of the bike. That will include the left and right dropouts and all the tubes. We&select File - Export and export all these items as a single STEP file. We&repeat this process for bolts and the derailleur hanger, the seatpost clamp and again for the various logos that will appear on our frame. We&then open CADRays and select File - Import and read in each of the STEP files exported from FreeCAD. We&define the up direction in the model space as being the Y coordinate. Looking at the models brought into CADRays, we can see that they&each defaulted to a shiny gold colour. We can go through each of these models and assign a unique material type and colour. You&probably want to experiment with different materials. In this example, we&select metal for the frame and right click on the color square to select a shade of green. For the derailleur hanger and bolts, I&also choose metal, but...