... ..) but I can't substitute my blocks for them nor will it let me substitute any of your blocks for them. Thanks Andy. I hope you had a nice time at the coast. I've been substituting blocks in TurboCAD* as a test without any problems. Admittedly I don't have anything meaningful to replace them with, and I don't really know what I'm doing. But the process seems to work. Here's the recipe I used, 1. select the one you want to replace, and off you go: 2_291626_410000000.png Unfortunately you have picked a different Z-axis zero for your blocks. Mine use the base of the chair (timber top) I have used the rail top as a reference for everything. However I can easily make it an option for the blocks. Give me a chance to eat some roast beef and Yorkshire pudding, and I will then post another file. *TurboCAD Deluxe 20.2 64-bit cheers, Martin. posted: 30 Jul 2018 01:13 from: Martin Wynne Hi Andy, Here's another file ...