CompuServe Thread

#Boolean //memory

11 messages in this thread
#193207From: AnselmoSep 29, 1995 6:13 PM
Hallo Bob. Im working with boolean operations. I have to substract 2 objekts from each other. But the on one has nearly faces. With 196 MB RAM adressed with Quemm and a Swap path about nearly 600 MB free space I get an error message -not enough Ram for that operation. Is it possible to calculate the mem requirement before? Anselm
#193220From: Robert C. RitgerSep 29, 1995 7:51 PM
Anselm: >> But the on one has nearly faces. << I think you left out the number, yes? Most of the times I am able to avoid using boolean operations in 3DS. I have a Solid Modeller to do anything complex. My first suggestion is to come up with a modelling technique which does not require a boolean operation. Can you describe the objects which you are working with? Maybe we can come up with a way around the boolean operation. It sounds like you have an extremely complex object, why so many faces? If this is a common experience for you, you may wish to use a program like Optimize to economize on the number of faces in your meshes. – Bob Ritger
#193295From: AnselmoSep 30, 1995 1:39 PM
>> But the on one has nearly 25.000 faces.ore more << When I wrote this message my compi was buisy since nearly 45 min. before failing totaly. My 3D Lofted object had to many curves in the 2D shaper depending on the .ai path importet from Photoshop.!!!! As I told you, I lined up the segments. and you can't imagine, the boolean operation works!!!!!!!!!!!!!!!!!!!!!!!!!!!! Thanks Anselm
#193237From: Jonas Ruikis [ADESK]Sep 29, 1995 8:45 PM
Hi Anselm, << Im working with boolean operations..>> In addition to Robert's suggestion, there are several tips on pg 7-56 of the 3DS Ref Manual that you should try. jonas[adesk]
#193240From: Terry MillerSep 29, 1995 9:59 PM
Hi Jonas, Perfect timing, I'm also having an (unexpected) boolean problem that you may can help with. I modeling a turbine type compressor. The main body looks something like an accordian. I created 32 pass tubes to go from one stage to the other and then boolean'd em all into the main body. No problem with the boolean operation, but now when rendered, it looks like it is in "Flat" shading mode. I applied mapping coordinates and the material again, same thing. I've tried changing from phong to metal, no change. I thought *maybe* I had exceeded some kind of face limit after the boolean, there are only 16K (and some change) faces in the object. If I try to tesselate, even at "1", it says object to large. I grabbed another object in the project and rendered it, and it looks fine. I *can* smooth it out with autosmooth or the IPAS smooth, but that then ruins the pass tubes. I am quite confused at this point, any thoughts? Thanks, Terry
#193260From: Jonas Ruikis [ADESK]Sep 30, 1995 12:54 AM
Hi Terry, <<.. any thoughts?..>> Have you checked your smoothing? See pg 7-127 in the 3DS Ref Man. In particular, note the picture on pg 7-133. jonas[adesk]
#193271From: Stephen C. LevySep 30, 1995 3:45 AM
Terry, It sounds to me like you've got lots of TINY faces around the boolean joints… that happens… Two ways to fix it I know of: Easy way is to select the whole object, then Modify/Vertex/Weld (Selected). This'll often work. If it doesn't, or only partially helps, you'd best brush up on your vertex welding, because you're probably going to have to do it by hand, by zooming way in on the joins, then individually welding the extra vertices. An alternative would be to try 3D scaling the object, say 25%, welding selected vertices again and then rescaling 400% to get your original size back. Be careful when doing this scaling thing, though or you could wind up welding more than you want!!! When trying stuff like this, lots of Saves and Holds after successful steps are crucial so you don't shoot yourself in the foot. Hope this helps! SCL
#194401From: Eric T. PetersonOct 7, 1995 2:48 PM
When doing boolean functions I find that there are many things that one must be aware of, such as: 1. The amount of faces that are in your scene in which you are trying to boolean. Many people have said that when exceeding the 65000 face limit, there will be a boolean failure. 2. Another problem is that boolean doesn't seem to work well with triangular faces…well unfortuantely, that is most of 3ds models. After all 3ds is based upon polygonal based modeling (aka triangles). A suggestion to this problem is to force a lofted shape to become more grid like in face composition. Alot of models that have triangular faces, all extend from on vertex. Force your model to goto other vertices by refining the image in the 2d shaper. Then re-loft. This will then create a better face construction (more grid like). If you are making a model that is lofted and tweened from one different shape to the next, you will notice that the face structure is also grid like, which will make for a better boolean in the editor. 3. Another quick point that I have noticed, optimizing an object or tesselating an object could be both harmful and beneficial. If you object has triangular faces, then by creating more triangles, you could be causing an instance where your first object does not make a proper cut or fails to cut (boolean-subtraction). On the other hand, by tesselating a grid-like faced object, you may be increasing the chance of success. None of these suggestions are written in stone, but keep an eye on them while modeling and booleaning, you may see that some of these suggestions may work to aid you in you quest to boolean better and more successfully. Good luck. P.S. if you are doing planer booleaning…consider SCALPEL as an option; I hear they are working on a spline based program as well!! Later, Eric
#194407From: Terry MillerOct 7, 1995 4:47 PM
Eric, Thanks a lot for that reply. I usually have pretty good success with booleans. I have found that they are somewhat inconsistant sometimes. If it doesn't work the first time, just keep asking and it just might. I never did figure out what happened with the last one I tried though. The object just refused to render in anything but flat shade (or the appearance of that anyway). I just went another route to get the same results I was looking for. That's one good thing about 3DS, the cat always get skint, one way or the other. Thanks for the suggestions, any boolean insights are always welcomed. Terry PS: I also received a couple of replies to this from Jonas and others. In the process of installing Tapcis 6 (and quitting smoking AHHHH!!!!) I lost those files. So if you were one of those who responded, and you see this….Thanks. I'm sorry I wasn't able to respond directly.
#194459From: Eric C. PetersonOct 8, 1995 1:33 PM
Howdy, On booleans: Ah, I had missed this thread! Of course, now that I search thrice daily for messages to 'Peterson' I'm bound to come across yours, too. I never get the 'Please Adjust Geometry' message anymore. Here's why: First, when you boolean objects with the 'Weld Vertices' option ON, it DOESN'T always work. Second, when you loft objects with the 'Weld Vertices' option ON, it DOESN'T always work. Thus, BEFORE and AFTER every boolean operation, select the object and do a modify/vertices/weld/selected. You're going to lose mapping anyway, so it doesn't matter that you lose mapping prior to the boolean. I have successfully boolean trimmed the same area of the same object SEVEN times with radically different shapes. Take a look at the fantail of my Enterprise model; it was done with five successive booleans to define the hangar door recess, the control cabin, the cutaway below the hull, and the fantail plan itself. The thread has already mentioned the problems with re-smoothing booleaned geometry. I have experienced an odd problem with a failure of autosmooth to define the booleaned intersection properly, so in the worst case I'll detach out the adjoining surfaces into separately smoothed surfaces. This seems to be related to the unusual configuration of the many small triangular faces along the intersection, even after they've all been globally vertex-welded. All faces in Studio are triangular. Even if you can't see the diagonal in a square 'face', it's there. However, some of the algorithms seem more reliable when meshes are constructed of nice face pairs. Perhaps this goes back to the original Autodesk insistence that DXF faces always have four points… Booleaning WILL fail if the total face/vertex counts of the output object exceed maximum values. Likewise, booleaning may fail when one object or the other is re-entrant, or doubles back on itself in the area of intersection. -E
#193296From: AnselmoSep 30, 1995 1:44 PM
Thank you very much. I'm working with 3DS just since 1,5 month. I wrote the manual and the 3DS inside step by step but it is to much in this short time.Thank you for your help!!! Anselm