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xmb
09-26-2002, 04:41 PM
hello xsi-friends

can anybody tell me if there is a way in xsi to model like in the subdivision-mode but actually be able to turn the finished object into nurbs?
or is there a possibility at all, to convert polygon models into nurbs?

thanks for help

ggg
09-26-2002, 07:56 PM
ApplyOp "PolyMeshPNet", ""
but its not ready for production yet

xmb
09-27-2002, 03:15 PM
what?

ggg
09-27-2002, 03:38 PM
???
select polymesh and run the command. there's no button for it

xmb
09-27-2002, 04:36 PM
it doesnt work
ok, again the question:

how can i model in the polygon-subdivision mode (extruding polygons, move, etc.) and then have a nurbs object?

is that something called subD?

xmb
09-27-2002, 04:49 PM
thanks for the pity

ggg
09-27-2002, 04:50 PM
I took it back sorry

the command definitely works in ver 2

tell me the step where it doesn't work

xmb
09-27-2002, 04:55 PM
ok

i've modeled an object with polygons. when i increase the quality of the model (geomapprox) it will get just too big for working nicely sooner or later. thus i'd have it rather in nurbs...
so how can i convert the model to nurbs?
and how can i model in nurbs like polygons, where i can extrude particular "faces" (polygons) but in nurbs.

so then i've tried your command, i copied and pasted it into the script window and in the little script line after selecting the object. it says "error, bla bla"

?

ggg
09-27-2002, 04:56 PM
in a minute

xmb
09-27-2002, 05:01 PM
i started with

primitive>polygon mesh> cube

then i extruded particular polygons, edges, deformed them, cut, pasted, just modeled the entire object and increased it's geo-approx with the + key to see it smooth. it got very complex. so i guess with nurbs you get a very smooth object with less data/pointcloud/faces amount...

ggg
09-27-2002, 05:15 PM
"""""""""""""i've modeled an object with polygons. when i increase the quality of the model (geomapprox) it will get just too big for working nicely sooner or later. thus i'd have it rather in nurbs..."""""""""""""""""

-use the + and - buttons to go up and down in subD level as needed while working

-or work on parts of your poly mesh model and re-merge them or unhide the merge whenever you need to see the whole result.

-you are probbaly already aware of this but working procedurally on everyhting including transforms will eventually slow you way down, so its good to freeze the operator stack once in while or work in immeadiate mode

""""""""so how can i convert the model to nurbs?
and how can i model in nurbs like polygons, where i can extrude particular "faces" (polygons) but in nurbs.""""""""

-you can replicate this somewhat in NURBS with putting curve to loft from on deform by surface etc but its not organic like poly modeling

"""""""""so then i've tried your command, i copied and pasted it into the script window and in the little script line after selecting the object. it says "error, bla bla""""""""""""""

-try putting this in your script editor and press run:

CreatePrim "Cube", "MeshSurface"
SelectObj "cube"
ApplyOp "PolyMeshPNet", , siUnspecified, siPersistentOperation

-unforutnatley the Pnet commend does not yet have any parameters to adjust it and if left procedurally dependent on the source mesh will get way slower than SubDs.

-the main issue is to achieve certain shapes, NURBS will be much faster and polys or SubDs for others

xmb
09-27-2002, 05:23 PM
thanks much.

i know that i can - & + - and the workflow is cool... i just thought there is maybe a way to convert polys to nurbs.

most professional guys animate with nurbs, when you see making ofs like jurassic park there you see the guys animating the dinos in nurbs, but having a smooth model.

anyway
thanks again for help

ggg
09-27-2002, 05:24 PM
Originally posted by xmb
i started with

primitive>polygon mesh> cube

then i extruded particular polygons, edges, deformed them, cut, pasted, just modeled the entire object and increased it's geo-approx with the + key to see it smooth. it got very complex. so i guess with nurbs you get a very smooth object with less data/pointcloud/faces amount...
yes especially since by + upping the subD level it is doing it to the entire surface not just where you may want or need it. You can do local subD but it has its drawbacks, better I think just to put the extra geo in exactly where you want it and then subD to level 1 or 2. I don't ever work higher than one maybe 2 levels of subD ever since subdivison quite literally is doing just that at avery geometery element and not optimizing where more or less geometry is needed to maintain a smooth surface

ggg
09-27-2002, 05:30 PM
Originally posted by xmb

most professional guys animate with nurbs, when you see making ofs like jurassic park there you see the guys animating the dinos in nurbs, but having a smooth model.

yes they use NURBS patches and have TDs to help them ;)
and there are some decent apps like Paraform that their modelers use or sometimes in house conversion tools to help them.

xmb
09-27-2002, 05:34 PM
you think they're not modeling directly in nurbs?
i find poly-subdivision modeling more comfortable than nurbs because you can extrude faces (having an simple object) and apply geo-approx at the end.
but nurbs are definately cooler when you're able to work with them as good as with poly-subdvsn.

so are there any conversion tools for me out there or do i really have to learn hardcore nurbs modelling...

ggg
09-27-2002, 05:51 PM
Yes I think they are working directly in NURBS.
I think its a good idea to learn some "hardcore nurbs modelling" anyway and if that is of interest use Maya instead, NURBS modelling in XSI is lacking with just a few decent tools like continuity. Paraform is a popular tool with some hardcore modellers.
SubDs are good for organic surfaces but not exact or efficient enough for smooth or some machined surfaces, and Nurbs UVs are generally much easier to texture. XSIs subDs are though very fast and since SI is concentrating on them expect them to be even faster with more modeling supporting tools in ver 3. The amount of geo you can display and deform interactivley in ver 3 is an amazing leap forward from what little I have seen.

Sorry I am not aware of any great converter out there for polys to nurbs that comes close to being as efficient as bulding the nurbs surface yourself with far less geometry.

For NURBs modeling try Rhino, Maya or Paraform. For SubDs I'd stick with XSI. I prefer Houdini for the mix of both with lots of supporting tools and you can convert in there too but it is also not going to give you as efficient a NURBS surface as you could make yourself.

Another way to convert is to ray, cast, project, or deform NURBS lofted curves or surfaces onto poly surfaces and this can work quite well with patience and time.

xmb
09-27-2002, 06:00 PM
nononononono, i will never use maya. i hate this program, i really dont like it and its interface, workflow, everything. i'm in love with softimage.
if not nurbs in softimage then only in rhino, no maya.

ggg
09-27-2002, 06:15 PM
I wasted much of a year of my life using Maya so I understand.

Polys in XSI don't yet work with some defoms but shrinkwrap as Ed suggested is decent, especially if you line up your geometry in detailed areas and then use the result to make a wrapper and target and do it again.

xmb
09-27-2002, 06:46 PM
cinema4d & maya are the most stupid 3d applications out there in my opinion, but that's just my opinion.

but alot of people were doing nurbs modeling in si-3d, is the nurbs modeling in xsi not as good as si-3d or even better?

ggg
09-27-2002, 07:06 PM
about the same, SI was way behind alias getting things like trims etc and XSI is way behind Maya now for NURBS IMO.
For the example you gave of jurassic park they also had many of their own tools beyond SI, some of which were incorporated into it.
The fact that it might be easier to make a car in SubDs than Nurbs in XSI shows how much the NURBS tools in XSI are lacking, not how great SubDs are as making a car with them is like typing with oven mits on mainly because getting an exact surface curve requires far more points and fudging around with points and you can't make indents or booleans in the cage of subDs and have the surrounding surface maintain its original nice smooth tangency like you can with NURBS trims. Look a the guy here hwo tried to make a door handle indent for his car with subDs, best wya is to apply a bolean afte the subD and thats slow and still can ruffle the surrounding surface without a redicoulous amount of subD levels.
BUT for a head or body SubDs blow NURBS away IMO for ease of use as you probabaly agree. I guess all we can do is hope that SI adds more options to their subDs such as cardinal and bezier control handles and more control of the subD surface such as optimization if possible. SubDs in XSI 3 are supposed to be awsome...

xmb
09-27-2002, 08:31 PM
where do you know this from, what did the doctor tell you?!?!

EAP!
09-29-2002, 02:21 AM
sorry to but in on both your guys' conversation but i do feel i can add a bit:

In early cg, in was all NURBS. But, as the game industry has grow exponentally over the past 10 years or so the speed and workflow of using polys has improved modeling immensely. Although they still use NURBS for much of the film industry the gaming industry has been wa-a-ay bigger for many years now. I believe IMO that NURBS will die out in the coming years. This is for the simple fact the computer speeds and support are becoming so good that working on a SubD mesh is almost(or is) just as easy as working in NURBS...

(XSI, MAX user)

-EAP!

xmb
09-29-2002, 11:38 AM
you say it's almost or just as easy as nurbs...
but in my opinion subd's are much easier, especially for organic objects. i find nurbs modelling more difficult, but i would really love to be able to do more with them.
how can nurbs die out, if they are more precise for things like mechanical models, industrial design, but even organics.
all the making ofs i see show nurbs wireframes, think just about jurassic park 1-3. but i may be wrong... especially because i've read the making of jp3, where they had to make the skin and body deformations.

so what do guys like ed harriss think for example?

and do you think subd's can replace nurbs at all? (for all models)

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