which is the solid modeling kernel based on csg

Y

yogesh

Guest
hi all!!

which is the solid modeling kernel which uses csg algorithms??

both parasoid and acis are based on b-rep...
is there any such modeler availabe which is based on csg???

if not ( that is my sure speculation) then can we say that csg
representation is obsolute..
i posted one earlier message regarding csg and brep and someone told
me that in autocad we can build the object using csg
operations(union,add,and subract etc..).but autocad is based on acis
kernel which uses brep representation..
now i am more confused..
so how will one differentiate between building a model using csg
techniques and storing them in brep...

regds,
yogesh joshi
 
ypjofficial@indiatimes.com (yogesh) schrieb:

both parasoid and acis are based on b-rep...
is there any such modeler availabe which is based on csg???

if not ( that is my sure speculation) then can we say that csg
representation is obsolute..
i posted one earlier message regarding csg and brep and someone told
me that in autocad we can build the object using csg
operations(union,add,and subract etc..).but autocad is based on acis
kernel which uses brep representation..
now i am more confused..
so how will one differentiate between building a model using csg
techniques and storing them in brep...
Click to expand...
You better look for "construction history" instead of "csg". Today the
ability to handle freeform NURBS surfaces is a must even for
low-priced products, and when you already have the surfaces then you
can build the solids from them. You will hardly find anymore a "real"
csg modeller which only enables to construct solids from primitive
bodies (as good old AME did in AutoCAD R12).

Solid Thinking (http://www.gestel.it) is a sample for a product which
shows the complete construction tree and lets you browse through it.

Tom Berger

--
ArchTools: Architektur-Werkzeuge für AutoCAD (TM)
ArchDIM - architekturgerechte Bemaßung und Höhenkoten
ArchAREA - Flächenermittlung und Raumbuch nach DIN 277
Info und Demo unter http://www.archtools.de
 
Constructive solid geometry (csg) let you CONSTRUCT a solid by combining
basic shapes.
Boundary representation (brep) rather descibes the RESULTing body in terms
vertices, edges and faces.
Kernels basically build a brep from a csg description while feature
recognition tools do the reverse.
Autocad calls acis csg functions directly, while feature-based CAD in fact
translate the feature tree into a sequence of csg operations. By doing this
smartly, they can avoid rebuilding the whole body from scratch when a
parameter is changed, do rollback and such things. This is why csg is
considered obsolete in end-user tools, but still very important in kernels.
--
Philippe Guglielmetti - www.dynabits.com
 
On Sun, 24 Aug 2003 15:42:33 +0200, Philippe Guglielmetti
<news@dynabits.com> wrote:

Constructive solid geometry (csg) let you CONSTRUCT a solid by combining
basic shapes.
Boundary representation (brep) rather descibes the RESULTing body in
terms
vertices, edges and faces.
Kernels basically build a brep from a csg description while feature
recognition tools do the reverse.
Autocad calls acis csg functions directly, while feature-based CAD in
fact
translate the feature tree into a sequence of csg operations. By doing
this
smartly, they can avoid rebuilding the whole body from scratch when a
parameter is changed, do rollback and such things. This is why csg is
considered obsolete in end-user tools, but still very important in
kernels.
Click to expand...

Interesting stuff...

--
Markus
 
Yogesh,

CSG is a construction methodology, not kernal level mathematical
representation.

Some very early 3D CAD systems (pre 1985) used CSG construction exclusively.
The last one I had any experience with was IDEAS V6i (pre master series).
Even then, 1987, the models were represented by NURBS faces and boundary
curves. I seem to remember a German program, same time frame, that claimed
to represent solids without surface information. I don't remember the name,
but I believe they were affiliated with H.P.


Regards

Mark




"yogesh" <ypjofficial@indiatimes.com> wrote in message
news:f88a27e4.0308232337.7ada2c7a@posting.google.com...
hi all!!

which is the solid modeling kernel which uses csg algorithms??

both parasoid and acis are based on b-rep...
is there any such modeler availabe which is based on csg???

if not ( that is my sure speculation) then can we say that csg
representation is obsolute..
i posted one earlier message regarding csg and brep and someone told
me that in autocad we can build the object using csg
operations(union,add,and subract etc..).but autocad is based on acis
kernel which uses brep representation..
now i am more confused..
so how will one differentiate between building a model using csg
techniques and storing them in brep...

regds,
yogesh joshi
Click to expand...
 
Bob Hanson Wrote:

Actually that was preSolid Designer and the product was called ME30.

Regards,

Bob Hanson

"jon_banquer" <jon_banquer@yahoo.com> wrote in message
news:bicbsk$7d8g4$1@ID-168325.news.uni-berlin.de...
A check of CoCreate's website shows that the product has ben renamed
from SolidDesigner to OneSpace Designer

Hope This Helps,

jon



"jon_banquer" <jon_banquer@yahoo.com> wrote in message
news:bic6v0$7hbho$1@ID-168325.news.uni-berlin.de...
I don't remember the name, but I believe they were affiliated with
H.P.

Company is CoCreate. Product is SolidDesigner. CoCreate is no longer
affiliated with H.P.

jon






"Mark Mossberg" <MUNGEDmark_mos@pacbell.net> wrote in message
news:CTg2b.5164$KO7.1869@newssvr27.news.prodigy.com...
Yogesh,

CSG is a construction methodology, not kernal level mathematical
representation.

Some very early 3D CAD systems (pre 1985) used CSG construction
exclusively.
The last one I had any experience with was IDEAS V6i (pre master
series).
Even then, 1987, the models were represented by NURBS faces and
boundary
curves. I seem to remember a German program, same time frame, that
claimed
to represent solids without surface information. I don't remember the
name,
but I believe they were affiliated with H.P.


Regards

Mark




"yogesh" <ypjofficial@indiatimes.com> wrote in message
news:f88a27e4.0308232337.7ada2c7a@posting.google.com...
hi all!!

which is the solid modeling kernel which uses csg algorithms??

both parasoid and acis are based on b-rep...
is there any such modeler availabe which is based on csg???

if not ( that is my sure speculation) then can we say that csg
representation is obsolute..
i posted one earlier message regarding csg and brep and someone told
me that in autocad we can build the object using csg
operations(union,add,and subract etc..).but autocad is based on acis
kernel which uses brep representation..
now i am more confused..
so how will one differentiate between building a model using csg
techniques and storing them in brep...

regds,
yogesh joshi
Click to expand...
 
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