DT, thanks for the file. It wasn't that hard to find "Autumn Leaves" through Google. I don't know if the purist's would call this HDRI. You're using a JPG image and not a HDR image. You're also using normal lights instead of a Luminance that works with an HDRI Environment. Other than those minor issues, it does render beautifully. It looks like you just went with the default settings, but I bumped them up. ACIS â€” Draft to Quality, Render â€” Full to Raytrace Full, edited the Point lights parameters, etc. It took about 35 minutes to render here. It might've gone faster if I wouldn't futz with it mid-stream. :-))
Dave C - One of the materials that Dave T created uses the XRay Transparency which is not found in earlier versions of TurboCAD.
Designer, Deluxe, (Professional, Expert, Basic), Platinum
Windows 10 Pro (1803), 64-bit