View Full Version : "Mystery" lines after boolean.

05-20-2006, 11:50 PM
Hi. Sometimes, I would have lines in my polygons after doing a boolean operation. Specifically, it happens when using the Subtract option.

Let's say, for example, that I make a hole in a box. There will be a line going from one of the points connected to the hole to a point on the edge of the box.

I don't want these lines on my polygons. How do I get rid of them?

05-21-2006, 12:11 AM
In short you can't. This line lets lightwave know that there is a hole in the side of a polygon. Visually you can not see this line when rendering.

05-21-2006, 07:51 AM
Could it cause problems with dynamics? I have been having problems with getting the wheels of a toy truck to stay on the truck. I'm thinking it has to do with the lines, but I'm not sure. They would try to stay, but they eventually go through the part that holds them. What is causing this?

05-21-2006, 09:10 AM
Now why in the world would you use dynamics to keep your wheels of a vehicle in place?


05-21-2006, 11:18 AM
Because it is a "toy" truck. The wheels are not really attached to the frame but are in seperate layers. By the way, I got that dynamic issue fixed, so I guess it wasn't the lines. Now I have to figure out another dynamic. I'll mention that in a different thread if I don't solve it. Thanx.

05-23-2006, 02:09 PM
first reply is totally wrong. These lines are 1 sided polygons... kind of like splines. By the way... YOU CAN SEE THEM IN RENDERS, and they are totally irritating. Don't worry though, to get rid of them, push W to open up the polygon statistics window. Make sure that you have the POLYGON SELECTOR tool on rather than point selector (push space to change this). Click the + sign beside the 2 sided and 1 sided polygons in the poly stats window. Now push delete. This ought to get rid of those annoying lines.

05-23-2006, 04:09 PM
Wongster, YOU are totally wrong. :)
You're talking about 2 point poly residue, which is something else. Silkrooster is talking about the concave polygon line which is always in there, and really doesn't even have anything to do with booleaning, but with the way lw works, and for that matter, every other polygon modeler.

05-24-2006, 01:49 AM
Just to add a touch of officaldom to this thread, Exception and SilkRooster are correct. The lines are because topographically a polygon is a single surface bounded by points. You can't have a hole in it so what LightWave (and indeed, every polygonal modelling package) has to do is make a new polygon that "wraps" around the hole. Because you don't normally want the hole extended to the side of this polygon it means that two of the edges of this shape have to be butted up to one another.


05-25-2006, 09:07 PM
Okay, I get what you are saying. Also, as I said last time I was on, I managed to fix that dynamic problem I was having.

I am having another one now. I know this is off the topic, but maybe you all might know what to do. I am trying to get a seperate collision object to push the toy truck but it won't work right. It will roll correctly if it is on a slanted surface, but if I try to push it on a floor or something, the wheels will not go with the body. What should I do to fix this?

05-29-2006, 04:10 PM
hm... I'm really just brainstorming here... Are the wheels on an axle? If not, could you model one? I'm not sure if this would help, but it might make things look more realistic. Good Luck!

05-29-2006, 11:04 PM
Yes, the wheels and axles are actually one piece items. There are 2 objects. Each consists of 2 wheels and an axle. Each one is a disc with 3 segments. The middle segment has been smooth shifted inward and is longer than the other 2 segments.

Maybe the dynamics aren't set right. I wish I can upload the zip file with the video, but I can't seem to get it uploaded. If you wanted a collision to push an object and have that object push another object, how would you do that?