More on EDGESURF

[Bella_Ciolla]

Hello, I am new but have a question about edgesurf command.

 

Its not necessarily about how to use it etc, I know all that, but does anybody know the math behind the edge surf? which happens to be a 'coons patch' I am not a mathematician but I have been researching and know almost everything about the math behind it except I dont understand the math. Even the math forums ignore me. I am needing to do an 'edgesurf' manually but I cant figure out the math involved, if anybody out there is capable of explaining it in simple terms to me, I'd be very very grateful, I cant figure this out. Thanks!

[ReMark]

Google the following just as it is typed:

 

"coons patch"+"how to calculate"

 

When the results come up click on the link entitled:

 

Topology Abstraction of Surface Models for Three-Dimensional Grid Generation written by Y.Zheng, N.P.Weatherill and O.Hassan.

 

It's a PDF file about 11 pages long. Go to page 5 and start reading.

[ReMark]

Here is another source of information about Coons Surfaces. It is an iPaper entitled Curves & Surfaces for Computer Graphics written by David Saloman of the Department of Computer Science at California State University. If you use the search feature in the upper right corner of the iPaper and type in coons it will take you to page 93, section 3.6.2, heading Four Curves. Coons Surfaces are covered here. Note that at the beginning of the iPaper the author lists numerous Internet sources for further information for curves and surfaces. The link to this iPaper is:

 

http://www.scribd.com/doc/7075120/Curves-and-Surfaces-for-Computer-Graphics

[Bella_Ciolla]

Wow thats so much for the references guys, this really helps out alot! I will read them this weekend, thanks again!

[ReMark]

You're entirely welcomed, Bella_Ciolla. I hope you find the information of some value.

[Bella_Ciolla]

I read through it today for a couple hours, for the most part it makes sense, but I get lost in the math a little though. But I have found the fundamental formula of it where it looks like you add two lofts together in the x and y direction than subtract something, but I am not sure exactly what your subtracting. I do, but I cant make sense of the math.

[ReMark]

I read through it today...but I cant make sense of the math.

 

I can barely balance my checkbook. I leave higher-order math to the professionals.

[Bella_Ciolla]

Lol yeah I hear you. Either way you totally helped me out alot with those links so I appreciate it. I think I have enough information to do what I need to do, I will just leave the higher order math to the professionals as well, and spare myself the headache lol. Thanks again ReMark! Happy Vday too.

[jatin1990]

hi i want to how i can subtract any object from the object created using edgesurf command in 3d plan? when i try to do it it show the basic object is not region. please help me on that topic.

[ReMark]

What type of object is being subtracted from the object that was created using the edgesurf command?

[ReMark]

It is my opinion that the object created using edgesurf should have been turned into a region first then converted to a surface. Then you could subtract the second object (a solid?) from it. I don't recall if there is a convert to surface command in AutoCAD 2004. I would have to look that up.

[ReMark]

I was unable to find such a command in 2004. However, there is a convtosurface command in 2009.

[jatin1990]

What type of object is being subtracted from the object that was created using the edgesurf command?

 

Actually i am creating bonnet of car which is made in 3d by using edgesurf command and now i am want to create holes in front end of bonnet for the accomodation of headlights. So how can i create hole in bonnet created by edgesurf command?

[ReMark]

At the moment, I cannot think of a way to do it using 2004. Doesn't edgesurf create a polygon mesh? As far as I can remember you cannot use Boolean operations such as union, subtract, interfere, etc. on anything by solids and surfaces. There might be some third-party software that will convert a mesh to a solid. I'm not sure.

[ReMark]

Mesh to Solid for AutoCAD

 

http://www.sharewareconnection.com/mesh-to-solid-for-autocad.htm

[ReMark]

Another option is the mesh-to-solid lisp routine mentioned in this discussion. There is a link to download the lisp routine (m2s2007.lsp) contained in one of the posts. Give it a try. Please let me know if it helped or not.

 

http://discussion.autodesk.com/forums/thread.jspa?threadID=469691

[ReMark]

I just remembered that there is a mesh-to-solid lisp routine here at CADTutor in the AutoLisp Archive forum (m2s.lsp). Probably a version of the one mentioned above.

[jatin1990]

Actually i am using 2006 version not 2004 and please update it in my profile. And i will check today all information u gave me and then i will update u about result.

i just check now convtosurface surface command is not working in 2006.

[jatin1990]

Another option is the mesh-to-solid lisp routine mentioned in this discussion. There is a link to download the lisp routine (m2s2007.lsp) contained in one of the posts. Give it a try. Please let me know if it helped or not.

 

 

i downloaded m2s2007.lsp file from ur given link but now i want to know how to install it into my autocad2006 version. please help me.

[ReMark]

Forum members are responsible for their own profiles. Update yours by clicking on User CP (top of screen) and selecting, from the column on the left, Edit Profile.

 

You have downloaded a LISP file. LISP is a programming language. Lisp routines are not installed they are loaded. To learn how to load a lisp routine visit the CADTutor AutoCAD FAQ section of this website (see top of page). The category you are looking for is titled Customisation. Please read the article How do I use an AutoLISP routine? That explains everything. If you have further questions just ask.