Boolean bug?

 From: Frenchy Pilou (PILOU) 10 Sep 2006  (1 of 14)
 Curiously the solid sphere A don't make the Boolean difference, the Sphere B yes! (yellow color is just for s"show", for the boolean operation I select first the base object (yet booleaned) above spheres :) Ps a volume in MoI (like exo.3dm) is a "surfacic" object or a "volumic" object? (surfacic against solid) EDITED: 10 Sep 2006 by PILOU Attachments:

 From: Michael Gibson 10 Sep 2006  (2 of 14)
 92.2 In reply to 92.1 Hi Frenchy, it looks like there are some problems with the surface of the interior wall - there are two spots where the surface forms some loops on itself. I've highlighted them here. The upper one is a pretty small loop. These kinds of "inside-out" loops can cause problems, especially in things involving intersections such as the booleans. It looks like that inner surface must have been the result of an offset of the outside surface - the offset needs to be cleaned up in this case before using it. Probably in this case you'd want to offset the outside edge curve instead of the surface - curve offsetting has more automatic cleaning up and trimming built into it than surface offsetting. Then revolve the offset curve to make the inner surface. > Ps a volume in MoI (like exo.3dm) is a "surfacic" object or a "volumic" object? > (surfacic against solid) Well, it's kind of both. But in common CAD terms this would be a volume, "solid" object. All objects are made out of surfaces. Surfaces can be joined to each other and share a common edge. If every edge of every surface is joined to another edge, then a complete connected skin is formed, which then can differentiate between the "inside" of the object and the "outside" of the object - this is a volume. This is the usual method of defining a solid for CAD programs, it's called a "Boundary Representation", or "B-Rep". Sometimes this is confusing to people since you can separate such an object and work on the individual surfaces of its skin and then join them together later. It is common for people to feel that being able to work on the surfaces means that an object isn't "really a solid". But this is not the case - if there is a way to determine the "inside" and "outside" of an object, then it functions as a volume. - Michael Attachments:

 From: Frenchy Pilou (PILOU) 10 Sep 2006  (3 of 14)
 92.3 In reply to 92.2 Thx for your solid explanations !) I suppose that some difficult to calculate this volume in unit m3 MoI can do that? Loops are made with no intention with my pen tablett on a small view ! (so I did't seen it :( So next time I will made better drawing :) So no bug yet in boolean function :) EDITED: 10 Sep 2006 by PILOU

 From: Michael Gibson 10 Sep 2006  (4 of 14)
 92.4 In reply to 92.3 > calculate this volume The geometry library that MoI uses has this capability. But there is no command to do it yet in MoI. I think that it will eventually be part of a set of "Analyze" tools that will have a new tab on the side pane. But probably a V2 feature. > Loops are made with no intention It is pretty easy for them to come accidentally on things that involve offsets, on any spots that have a curvature radius that is less than the offset distance. > with my pen tablet How is it going using the tablet with MoI? - Michael

 From: Frenchy Pilou (PILOU) 10 Sep 2006  (5 of 14)
 92.5 In reply to 92.4 < How is it going using the tablet with MoI? Like a dream :) And when the pen has a clicable button it's quasy perfect! Quasy because the Zoom wheel mouse function ist a little bit to emulate :) (maybe with the inkey arrow) + and - seems used for input numeric mesures

 From: Michael Gibson 10 Sep 2006  (6 of 14)
 92.6 In reply to 92.5 > + and - seems used for input numeric mesures I don't think that + is, but - definitely is. This is so if for example you're drawing a line, you can type "-5,2" to place a point at that coordinate directly. When you type that coordinate value, your keystrokes will show up in the coordinate value entry area in the bottom toolbar, just to the right of the Split/3D/Top/Front/Right view controls. - Michael

 From: Frenchy Pilou (PILOU) 11 Sep 2006  (7 of 14)
 92.7 In reply to 92.6 In fact Zoom with a pen (with clicable button as mouse right clic emulate) is not truely a problem :) As a pen graphic don't need realy touch the tablett You rotate your object in the space (clicable pen button pressed) flying your pen over the tablet on go on the Zoom Icon (screen bottom) disable the pen clic button and you can zoom easily :) More confortable than a mouse :) Ps the loops were made because I have taken the option Draw Curve / Free Form/ Sketch and not "Throught Points" So "loopings" can be easy created without my control due the micro pen movments :) EDITED: 11 Sep 2006 by PILOU

 From: Michael Gibson 11 Sep 2006  (8 of 14)
 92.8 In reply to 92.7 > So "loopings" can be easy created without my control due the micro pen movments :) Yes, that's definitely something that you should watch for. But in this case, it sure looks like those loops are the result of an offset operation that has a large offset distance in an area of tighter curvature. I think maybe the main shape was created by doing a shell of the outside surface to give it thickness? Doing a shell involves creating an offset surface, if the offset distance is large in an area where the surface has a tight bend in it, then it can cause the offset to fold over on itself like you have here. - Michael

 From: Frenchy Pilou (PILOU) 11 Sep 2006  (9 of 14)
 92.9 In reply to 92.8 < those loops are the result of an offset operation that has a large offset distance in an area of tighter curvature Right :) < then it can cause the offset to fold over on itself like you have here Right again :) So we must see in Zoom the curves befor some booleans functions:) So how increase the transparency? :)

 From: Michael Gibson 11 Sep 2006  (10 of 14)
 92.10 In reply to 92.9 > So how increase the transparency? :) Maybe clean your monitor screen? :) That's the easiest way for me, anyway :) - Michael

 From: Michael Gibson 11 Sep 2006  (11 of 14)
 92.11 In reply to 92.10 Seriously, though - you can adjust the intensity of the hidden edges if you would like them to be more pronounced. In the moi.ini file, find the [Hidden lines] section, it has this available: HiddenLineOpacity=34 This can be a number between 0 (totally transparent) and 255 (totally opaque). A higher number will make the hidden edges easier to see, but if they become too prominent they can interfere with your depth perception of the object, that's why they are set to pretty faint by default. - Michael