Boolean Messed Things Up a Bit....

[Ragtopjohnny]

When working on my model, we know we use Boolean for the window cut out, and today something odd happened.

My one piece fuselage was coming around fine this time, but the Boolean messed an area up between the main door and the wind screen.

I don't understand what is happening with this. I try to fix it, makes things worse. Can anyone give ANY suggestions on what to do here? I'd hate to go back to the two piece fuselage. May have to from the looks of it. Did not have this problem before...

Thanks in advance,

 

[Vitus]

Yep. Welcome to our world of Max mysteries. You probably did nothing wrong here - except that you started 3d modeling in the first place

Nothing really you can do about but clean up you mesh afterwards. Convert it to e-poly and make use of the welding tool, draw new edges etc. Cleaning up the mesh (mess?) after a boolean cut is a huge PITA but I guess that's just the way it is...

I slightly changed my technique anyway: I usually don't use the "Subtraction (A-B) operation, but instead use "Cut->Refine". That way your mesh will still be the same (or is suppose to anyway) but the second part "cuts" new edges. You can then manually erase the polygons you don't want (window cuts, or whatever). The advantage is, that before you delete these polygons, you can Adjust the cut. Sometimes some edges are just not cut properly so that as a result the window-poly is not closed. You can spot and fix this easily.

Good luck!
Vitus

 

[n4gix]

Vitus' suggestions are excellent.

One other step you can take would be to select only the polys through which you wish to "boolean", then Detach them temporarily to a new object.

Now, CLONE a copy of your detachted part for safekeeping...

Now, boolean on the newly cloned, detached part.

Do any clean up required.

When satisfied, select your fuselage, and Attach the result, select all vertices, and Weld using the lowest possible threshold (usually 0.001).

 

[Vitus]

One other step you can take would be to select only the polys through which you wish to "boolean", then Detach them temporarily to a new object.

Now, CLONE a copy of your detachted part for safekeeping...

Now, boolean on the newly cloned, detached part.

wow another very good idea! I never thought about that

 

[lionheart]

Thats how I do it also. Make a copy of the fuselage. One is the fuselage with window cutouts, one is the windows. They should cut identicle.

Now.. With cutting Booleans, note that its an algorithm that has to be 'happy' in its surroundings (objects) when its going to do a cut. One way to 'adjust' its happy spot is to change or 'match' the 'sophistication' of the objects. Thus, if you are cutting out a box from a super high polycount fuselage, then add segments in the box so its equal in sophistication.

Also, sometimes you have to 'move' the cutter around 'slightly', make a cut, and see if it works better. Just moving the cutter a little here and there will do wonders and will not be that much noticeable from the professional eye (dimensions). Sometimes cutting next to or through a rib section (verticle edges) will cause Booleans to sputter and make a mess.

If you are only doing a few windows, I suggest hand cutting them, especially if you are only doing a single side of the fuselage.

If you dont have the patience, then try Felix's fave; Shape Merge (next to Boolean). It cuts via a Spline(s) and does a fair job, but usually has a zillion left over Vertices, like Boolean will do. That is the beauty of hand cutting windows and things is that you have 'zero' leftover misc Vertices and its 'exactly' the way you want. Just have to be patient and make your Spline patterns to go by....



You can cut Vertices (lay them down into) the middle of Polygons when in Editable Mesh mode. Then convert to Editable Poly and connect the Vertices with Edges (Edge mode, Create Edge) and connect all the lines to make the windows and door lines..

This is now my fave.. Fastest and most exact..


Bill

 

[n4gix]

wow another very good idea! I never thought about that

One of the hidden dangers of boolean ops, especially in GMax, is that sometimes "stuff happens" in the most unlikely areas far, far away from where you actually made the cut.

This technique isolates the polys to be cut so that can't happen.

Like Bill O., I've found that creating new edges by "tracing" around a shape is the easiest way to cut simple shapes.

Doing a Shape Merge with a Spline Object is sometimes successful as well.

 

[Ragtopjohnny]

Thank you VERY much for all the detailed responses and techniquest to help clean this as Vitus says, "mess" er "Mesh" up. I appreciate everyone's input, may not be so helpless after all on it.

Thanks again! I never would have DREAMED of those solutions. This site truly is very helpful to the novice as well I am sure the seasoned modeler. Excellent resource.

Thanks Vitus, Bill, and Bill O. for ALL of your inputs....

 

[hairyspin]

A similar boolean problem and its solution (with screenshots) is here:- CombatACE forum

 

[Ragtopjohnny]

Thanks Tom, appreciate the additional info....

 

[FelixFFDS]

While this is a max/gmax thread, Fr. Bill's suggestion is practically the BEST process when doing booleans in FSDS.

Vitus' suggestions are excellent.

One other step you can take would be to select only the polys through which you wish to "boolean", then Detach them temporarily to a new object.

Now, CLONE a copy of your detachted part for safekeeping...

Now, boolean on the newly cloned, detached part.

Do any clean up required.

When satisfied, select your fuselage, and Attach the result, select all vertices, and Weld using the lowest possible threshold (usually 0.001).

 

[dmaher]

Yeah, I think Booleans are great tools and I use them a lot.
But I never use them on my export model. It’s a habit – and it is a bit superstitious.

I always duplicate my model to make a reference mesh and this is where I do my Booleans.
Then I manually cut the final shape on the original model by adding edges with vertex snap to ensure a precise trace of the cut.

As you know Booleans add vertices and edges in intermediate and unnecessary locations.
Plus Booleans combine objects and that often leads to errors in the normals.
Tracing a cut from a booleaned reference let’s me choose which vert’s I want and helps preserve the original normals.

For what it’s worth I think 3D modeling is somewhere between wood working and old-school drafting.
The basic techniques in drafting translate really well in 3D modeling.
Reference meshes (and reference splines + verts) are just like the ‘construction lines’ in drafting.
The hard work goes into laying out the construction lines properly (in 3D).
But the final mesh is just a clean trace.

 

[hairyspin]

...Booleans combine objects and that often leads to errors in the normals...

I believe that is why Milton recommends removing all smoothing before doing a boolean. I came across this in his excellent C162 tutorial series and wondered at the time why he did it.

Nifty idea dmaher!

 

[lionheart]

For what it’s worth I think 3D modeling is somewhere between wood working and old-school drafting.
The basic techniques in drafting translate really well in 3D modeling.
Reference meshes (and reference splines + verts) are just like the ‘construction lines’ in drafting.
The hard work goes into laying out the construction lines properly (in 3D).
But the final mesh is just a clean trace.

I totally agree. I am thankful I took drafting, and have done wood working and foam carving (car design) so I have a little bit of an idea of shape creation.. Anything helps...

 

[Ragtopjohnny]

Folks, appreciate the suggestions here on the windows.

Bill, on your making a copy of the fuselage, that helped too. I have a new twist: I turn that transparent, then fit in the glass. Worked out on the trial run, we'll see what happens in the future. I'll post renders later.

I really appreciate EVERYONE'S help here in these forums.