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Autodesk Multimedia Forum · Autodesk 3D Studio

#Invalid Rat Nest in DXF?

13 messages in this thread

#120299From: J. D. WILSONAug 25, 1994 4:53 PM

NO REALLY, an "Invalid RatNest" is what the error message said in 3ds3 when I tried to import a DXF from MicroStation ver. 5. We are trying to import a dxf file a little over 2.1 mbytes in size. G. Yost or someone must have sat up all night thinking up this little error message. I must say, we got a giggle out of this one. 🙂 What is a RATNEST and how do we get rid of it….. JD

#120306From: NICOLAS J. HOWERAug 25, 1994 5:43 PM

To J. D. We had one of these "nests" around a year ago , but as opposed to you, are still finding it difficult to laugh at it! Ours was being imported from ACAD12 and it turned out to be a spiral staircase mesh which was causing the rats to build nests. It was a long process of elimination before finally deleting the staircase, importing the rest of the project, and then rebuilding it in 3DS. Good luck! Nick Hower Blanchard Hower Associates

#120309From: Yost GroupAug 25, 1994 5:49 PM

You know… a ratnest is a nest of rats! Seriously, we did NOT invent the term. It's an AutoCAD term for a polymesh of 3 or 4 verts per face (triangles or quads). Getting an "invalid" error means that the data doesn't conform to the DXF spec for what a valid ratnest mesh ought to be. For _that_ information, ask around on the ACAD forum for the DXF spec (or look in the AutoCAD manual, if you've got it). – G

#120382From: Dietmar RudolphAug 26, 1994 2:51 AM

Gary, the official AutoCAD term is 'PFace' or 'PFace mesh' which must have something to do with 'Poly …' 🙂 3DS is the only Autodesk product I know of that calls these things 'ratnest'. Dietmar

#120428From: Yost GroupAug 26, 1994 10:23 AM

Believe it or not, the source code inside of Acad's PFace entity refers to them as ratsnest meshes. – G

#120846From: Dietmar RudolphAug 29, 1994 2:33 AM

Wonder what other little animals (e.g. b**s) are hidden in the ACAD source 🙂 Dietmar

#121576From: Jeff GlazeSep 1, 1994 3:08 PM

Gary, Where can I send you the latest issue of my magazine? Jeff

#121612From: Yost GroupSep 1, 1994 5:46 PM

3739 Balboa St., #230, SF CA 94121 – G

#122016From: Jeff GlazeSep 4, 1994 9:48 AM

Thanks Gary! My latest magazine is on it's way. Jeff

#122022From: Yost GroupSep 4, 1994 11:18 AM

Thanks, Jeff. – G

#121177From: J. D. WILSONAug 30, 1994 6:48 PM

Thanks for the reply! I will give the acad borum a shout… JD

#120383From: Dietmar RudolphAug 26, 1994 2:51 AM

JD, a PFace mesh or 'ratnest' is an object consisting of points, lines, triangular and four-sided faces of different colors and layers. It is implemented in DXF as a series of definition points (vertices) plus a list of faces, all hidden in another variant of the POLYLINE entity. You'll find the exact syntax specification in my book "DXF Standard" (d/l DXFBK.TXT for more info). Maybe Gary can tell us a bit more about what 3DS doesn't like with 'ratnests'. Dietmar

#121180From: J. D. WILSONAug 30, 1994 6:50 PM

Thank you, I will d/l the info right now…and will be looking to get the book asap. JD