Better use Join or Group or Union?

[Starblade]

I've build an object that is more or less a tube structure like a light tower in a stadium or a scaffold. Now I ask:
is it better to join the small tubes using JOIN or GROUP or UNION (and making just 1 object)? What is better for building objects? The tutorial says "Depending on the case,
joining might actually produce more optimized geometry than a union". Too vague for my taste. Any ideas? Any concrete examples from past experiences?

[william ford]

What the hell is a JOIN? I'll just ignore that one.
So this is a pole outside, pretty much right? I would probably group it(cause im lazy). But u should probably union it to your stadium.

[biXen]

In general you shouldn't join much. And you should only join if it's not a dynamic object.

I'd group it to the stadium, don't worry too much about it, just make a group structure, like stadium being root, benches to sit on being children of stadium, the feet on the benches being childrens of the seat and so on. As long as you make a big exit in the start someplace you can use it it's pretty easy to make a good group structure.

This is pretty much what I have done, but you should just experiment a bit.

[Starblade]

Originally posted by william ford:
What the hell is a JOIN? I'll just ignore that one. <font size="2" face="Verdana, Arial">"JOIN - As mentioned before, a join operation is not a true Boolean operation. It does the same as a union but with a different twist: it does not delete any geometry. As explained above, in a union all intersecting geometry is discarded, in a join however the objects are just clamped together keeping all the geometry intact. The objects can also be separated again if necessary even if they touch (unlike in a union). The only requirement is that the objects' vertices must not meet, if this happens, separation will likely fail.

Joining is useful if you have many objects that would be better handled as one, but you want to be able to separate them if necessary. Depending on the case, joining might actually produce more optimized geometry than a union. Like in the case of a plank pile, joining will result in fewer polygons than a union since union splits the surfaces but joining doesn't."

I normally go for unions, but since they say joining might actually produce more optimized geometry. it might be very useful. That s what I'm trying to find out.

[william ford]

Well that sound pretty usless except in that example, wouldn't help to many other things.

[Co&Co]

Also......when you have for example a pillar in your room (or whatever), personally I would substract it instead of grouping, because when you render your level the result will be much better (at the places where the pillar and room connects).