Hi Matt, thanks, I'm glad you like MoI!

The reason for the union failure is that the cylinders inside the wheels are floating just a little bit in front of the back plane of the main wheel part, they aren't touching - here is a zoomed-in view from the top of one of those wheels:



You can see the dashed lines for the edge of the cylinder and the back plane, there is a bit of space in between them, the cylinder is floating in front of the back face a bit.

To make the union work, these objects must be touching each other - and it is usually not a bad idea to make them actually stick through each other a bit instead of only exactly touch, but they must at least be touching.

It also looks like there is a bit of a slant to the cylinder piece's face - maybe this was done as an extrusion of a very slightly off-axis circle? It might be a good idea to draw a new cylinder in there to get a really regular end on it.

It looks like you're having some fun creating stuff!

- Michael

Thank you so much Michael. After Frenchy pointed that out I went back and did exactly that. As I figured, operator error.
I might as well apologize, in advance, for the slew of stupid questions to come, As I am completely hooked.

Thanks Michael

Matt

Well, no doubt you would have figured it out if MoI provided some information like "Objects do not touch", or something along those lines.

But I haven't quite figured out where to put such error feedback yet, and in some cases it is a bit difficult to determine the reason why something didn't work... So it might be a while before that can happen.

- Michael

How about just a generic place holder type of message such as,"Action was not completed." Just something saying it didn't work would be great, maybe a pop-up where the tool info is input? Or maybe the cursor changing to the "No Go" circle with a slash through it upon execution.
Your doing great stuff bro, like I said before, you've got me sold.


-Matt

Good idea, but pčeeeeease with someother sound....anything then microsofts default error soound....that booooooom