csg subtract key

[Fragmaster-B]

i have been looking at a lot of threads lately about the csg subtract key in gtk radiant..a couple of question for anyone, if every one says stay away from it ,why is it still in there? i know when u use it it leaves micro brushes which is bad ...also when is the correct time to use it?? and for what?

 

ty inadvance

[lassev]

That bloody key does nothing magical. There are fanatics who never ever consider using it, yet if you know what it does, you'll also know when to use it, and what kind of results it will give. Sometimes you can use it, and then correct the results to what you want them to be. Still, sometimes you know you shouldn't use it (with any complex brush) and you don't.

 

It is perfectly sound tool to use, when you are making a rectangular doorway. Yet, it may not give you the kind of smaller brushes you wanted to be left of the wall. And often it gives you long, narrow brushes that could easily have been avoided with basic clipping.

 

The only use I have for that tool is to make holes in floors or ceilings. So far it hasn't let me down.

[wedge2211]

Occasionally CSG Subtract can do something that the clip tool can't easily do, and those are the only times when I use it. It isn't a problem if you can use it intelligently.

[War Master]

I use to use CSG Subtract when I was a noob. I haven't got a use for it anymore. I mostly drag edges and vertices and use the clipper tool and that's all I really need to shape and manipulate brushes.

[Eldritch]

Originally posted by wedge2211

Occasionally CSG Subtract can do something that the clip tool can't easily do, and those are the only times when I use it. It isn't a problem if you can use it intelligently.

Exactly.

[Silverhawk2000]

Originally posted by wedge2211

Occasionally CSG Subtract can do something that the clip tool can't easily do, and those are the only times when I use it. It isn't a problem if you can use it intelligently.

 

I've read in posts and elsewhere that it's 'EVIL' and should not be used.

 

I don't know exactly what kind of errors CSG Subtract has caused to cause people to be so wary or afraid of it. I assume any errors it causes can be tracked down and fixed (with a little investigative work of course).

 

All I can say is that I have used it and have had no problems (yet) - Knock on Wood, rub the lucky rabbit’s foot, throw salt over your left shoulder.

 

I used it to create a Valve Wheel; you know the kind of think that looks like a steering wheel (with 4 spokes and a central hub) I attached this to the side of some pipes. It makes a cool addition to the map.

 

Here is how I made the Valve Wheel.

I created a square brush, arbitrary sides, 20 (4 units thick)

Then another of the same brush circles but smaller, also 4 units think, and inside the first brush.

Then with that brush selected, chose CSG Subtract. Delete the inner circle brush and Wham! You have a ring! It's pretty cool how GTK Radiant broke it up into a number of other brushes. To try to do that manually would have take me ages!. It compiles and runs fine.

 

I don't know about this 'micro' brush problem and what it's all about. I assume that you should never have a brush whose dimensions fall below 1 unit in any plane (X, Y, or Z) - I'm guessing here. Besides, 1 unit is very tiny in the game world. Realistically I would not see why anyone would need anything with any smaller dimensions than this (You might end up causing a black hole with your singularity - just kidding)

 

I use GTK Radiant and in the Grid Size setting you can go down to .5 and .25 of a unit. Now this does not mean that I am about to create .25 x .25 x .25 cubes. However it does not cause me any problem when I create a brush that is say, 10.25 units. Why 10.25, here is a good example of how I used it as a ‘work around’ to a problem that I had recently.

 

In my current WIP I created a Construction Crane; you know those big fixed cranes you see that help build sky scrapers and apartment buildings. Well, the boom of my crane has a steel lattice work (picture an X inside a box) which is repeated over and over again. Now the Vertical part of the crane did not cause me any problems when I stacked these X-Lattice Boxes one on top of the other (to form the tower part), but when I tried to create the Boom I ended up getting this weird error message (I don’t remember the exact error name, something like WM_blah_blah_blah excceded 64 points) sample points (#,#,#)

 

Did some research on the groups here and found out that basically, you cannot have a really long series of brushes in a row whose co-ordinates fall on the same plane. People have encountered this problem when trying to have a whole series of pillars or fence posts in a row. To work around this problem, I created a shorter boom-section, then repeated this section but moved it down .25 and over .25. When playing the map it is almost impossible to notice. You would have to know it’s there even to begin trying to hunt it down. This way I was able to have a long crane boom, and not have to trash my model.

 

If anyone would like me to send them the prefab of the crane then let me know and I will e-mail it to you.

You can use it in your map, I only ask for a small mention somewhere (in the read-me file or whatever).

 

e-mail me at jedi.knight@sympatico.ca if you want the crane. Just put 'PREFAB Please' in the subject, that way it will stick out and not get deleted with the junk mail an spam.

I'll do my best to send it out when I have time (weekends usually).

 

Oh yea, I forgot to mention, the cable and hook at the end of the crane form a pendulum. When the hook slams you in the head it kills you. Ouch! It swings slow though so not much danger.

 

God, I love the GTK Radiant Editor.

 

[wedge2211]

Hey...Why not make your valve wheel out of curves?

 

THat's one of the uses I've had for CSG Subtract in my maps, cutting a hole in an n-sided brush. It's how I made the walls of the White Temple in CotA.

 

Originally posted by Silverhawk2000

I don't know about this 'micro' brush problem and what it's all about.

 

Someone explained this to me once, if you use CSG Sub on a small number of big brushes, it's okay, but if you, say, use CSG Sub with a big ol' rectangle stuck in the middle of the x-wing physics prefab, you'll be chopping up a LOT of small brushes, and you might end up with loads of little brush fragments hanging in space. I'm not sure exactly what the problem here is cause I've never seen it, but rule of thumb is, don't use CSG Sub on a load of brushes at once.

[Silverhawk2000]

Originally posted by wedge2211

Hey...Why not make your valve wheel out of curves?

 

... don't use CSG Sub on a load of brushes at once.

 

I'm no curve expert yet wedge. But if I get the time, I might give it a go for fun.

 

Don't use CSG Subtract on multiple brushes at once... Good advice. Every time I have used CSG Subtract I have only used it when trying to 'cut away' from another single brush. I can see where cutting away from multiple brushes may cause problems for the engine.