<font color="yellow">Why does the truss have to be milled from a single piece of material? </font><br /><br />Good point, of course it almost certainly doesn't. <br /><br />Something like a truss would typically be a fabricated part, not a machined one. IOW, you make it out of flat bar, angle bar, round bar etc and all you really need is a cutoff saw, welding and grinding.<br /><br />However, if the stuff you need to attach to it needs precise location of mouting holes etc, you find that the accuracy of fabrication is not even close. Welding warps things so there's basically no such thing as a precision weldment. So after it's all welded up, you take it over to the milling machine to put finished surfaces and holes in it. <br /><br />There are other ways to deal with this than taking the whole monstrosity over to a huge 5-axis milling machine, but on the other hand, having such a tool available would be pretty cool for the designer. For one thing, your certainty that things are where they belong on the finished product would be much higher.<br /><br />Oh man, would I like a peek under the tent!<br /> <div class="Discussion_UserSignature"> </div>