PORSCHE GT3 - NURBS modeling tutorial

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  11 November 2003
Please keep posting. Want to see how you build car with nurbs .
 
  11 November 2003
1.)

Create 4 curves to match the prints. THen rebuild them using the rebuild tool, and first rebuild all curves with 3 spans, then rebuild them having that numspans checked in the options.
SHould get something like mine.

2.)

Use birail2 to create a surface, selecting the curves in order.
Make sure the ends are snapped.

3.)

Now you know what to do.

4.)

Use birail 3+ to create a surface.

Here is the final result for today:
http://www.vertexstudios.net/Porsch...nishedfront.jpg
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Last edited by TheShaddix : 11 November 2003 at 04:47 AM.
 
  11 November 2003
hmmm...interesting, keep going.
I'm following (even tho it looks just like what i was doing before)
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  11 November 2003


This is the area where many people, including me, usually find themselves confused. THe question is: how to do it and what to use?
Ill be working on that area tomorrow, so stay tuned for updates.
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  11 November 2003
I guess "trim" and then "stitch"

....am I right? lol, i dont really know nurbs tools, so thats just really 70% guess.
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  11 November 2003
my contribution...

Okay, I'll help out with this thread... I think I can model the wheels pretty accurately, if not, you dont have to use my method and you can use TheShaddix method (when he gets to it)

but here's my wheel tutorial...
..::[ Modeling the Wheel ]::..
_____________________________________________

well, let's start it off...
1) basically... set up your perspective with a picture of the tire attached to a plane, and match it up as best you can with the center of the world... I used:

Translate.X = -0.161
Translate.Y = 0.377
Translate.Z = 0.133
Scale.X = 15
Scale.Y = 15
Scale.Z = 15


(since the wheel is being made in nurbs, I made the plane a polygon plane, so you can turn off "view polygons" if at any time you want it to not show up in one or more of your perspectives)

then you want to goto "create >> nurbs >> nurbs circle" and, deform it to look like the inner spoke curve. you then want to duplicate this curve (after you've fit it to the shape of the reference) and scale it up a bit, and reshape it to fit the outter spoke curve.

(do not forget to change the pivot points of the circle to center of the world, as we are rotating these deformed cirlces!)

once you've done that duplicate them both 36º (for me, it was in the Y direction, but it depends on how you set them up in the beginning... you'll figure it out) until you come back to where you started. This should leave you 20 curves, in this fasion:


(as you can see, I also added that little circle in the middle for the little "nub" as I call it, that sticks out...pretty simple)
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Last edited by jlmakes : 01 January 2004 at 01:56 AM.
 
  11 November 2003
my contribution...

2) now that that's done, create a nurbs circle... transform as such:

Scale.X = 4.72
Scale.Y = 4.72
Scale.Z = 4.72


select this curve, and apply a planar surface to it; after that, rebiuld the surface with a U,V of 7,7.

(this is assuming your using the same scale as I am for the reference plane... which was 15,15,15 if you recall from step one... otherwise, adjust to your own scale to the edge of the rim in your reference pic)

now, select all the curves you just made (except the nub) and bring them to a little bit outside of the (front of the) circle. Now, select the outter spoke curves, and extrude them inwards (towards the circle) with a distance of... oh, about 1 unit. (it all depends on how think you want the rims and how far out you moved the curves)

now here's the tricky (but crucial) part...
select the first extrusion, and the planar surface. Go to the surface fillet option box and check the box create curve on surface (this is crucial) and then, uncheck reverse primary normal (if it's checked) and check the box next to reverse secondary normal (if it's not checked)... and create a surface fillet for each and ever extrusion you just made (with a radius of about 0.08).

you should now have something that looks generally like this...


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Last edited by jlmakes : 01 January 2004 at 01:56 AM.
 
  11 November 2003
my contribution...

3) Now on this step, it starts to look cool!! What we need to do, which is somewhat tedious, is select each extrusion, and the planar surface, and use the Intersect tool, this basically just creates a curve on the surface where the 2 surfaces intersect, which is exactly what we want...

Now select one of the extrusions... and select the trim tool. The mesh will suddendly turn all dotted white... and it'll show you all the seams in think bold white lines (**Note: those think bold white lines are the intersections we just made!!) ... what you want to do is select the region that you want to KEEP... so, select the part of the mesh that is BEHIND the wheel (the side that the fillet is on) and then press enter. repeat this for ever single extrusion.

once you've done that... do the same thing for the planar surface... select it, get the trim tool, and select the region that you want to keep, which is any part except inside the area that extrusion passes through (you should understand how the tool works by now!)

after doing all that, you should have a cool thing that looks like the following:



It's coming along nicely isn't it? you can see the shape of the wheel developing. Now, onto step four... phew!
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Last edited by jlmakes : 01 January 2004 at 01:57 AM.
 
  11 November 2003
my contribution...

4) okay, well, now its time for some for some of the same stuff we did last step. select all the outter spoke curves (the ones you used for the extrusion, which you hopefully didn't delete yet) and make a planar surface. With this surface select, Rebuild it with U,V of 3,3. Now, move this back towards the wheel again so, it's just barely in front of the end of the extrusion.

(clarification... i'll show a picture of it, but just so you understand, this is assuming your curves are still infront of the wheel where we put them prior to the extrusion. And what we want to do, is move them to a little bit in front of the end of the extrusion that we made with these curves)

so, if that wasn't clear, which im not sure it was... here is a pic to demonstrate...



so, once you've done that... you want to keep that new planar surface selected, and select each extrusion and (using the same fillet settings) surface fillet all of these extrusions to the new planar surface.... this will result in the following:


pretty damn cool eh? (i'm kinda impressed myself... I never really done a wheel like this before!... it's kind of guess and hope it works!)

(now if you really want to be picked... like I am... you can intersect all of the extrusions with the new planar surface we made, and then use the trim tool so the ends arent hanging off...regardless if they wouldn't really show in a render, im a perfectionist, so yah... this is I guess for the perfectionist/advanced users.)

so now... whoohoo, step five...
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Last edited by jlmakes : 01 January 2004 at 01:57 AM.
 
  11 November 2003
my contribution...

5) Now we get into the nitty gritty hello kitty tedious work... its basically all we've been doing (extrude/intersect/trim/)... but it's almost our final step. there are only 2 more steps after this...

so, now... all those other curves (which I had hidden)...all those inner spoke curves, all the smaller ones... it's time to deal with those. Select all of those, and extrude those slightly past the back of the wheel (I used a distance of 0.75, but it'll be custom depending on what you used.) ...see this example:



now... what we want to do is with all those extrusions selected, intersect them with the planar surface that they are extruded through (the second planar surface that we made... as seen in the pic above)

then, the same old same old... surface fillet same settings, except this time I used a radius of 0.35 (but it depends on your settings, again) and then do the trim's... etc, I feel like at this point, if you havent figured out the process and/or how to use these 3 tools: extrude/intersect/trim... you need to not be doing this level of modeling, because I feel I've explained it very well... and if you still dont get it, either I'm mistaken in the amount of quality that this tutorial covers those tools, or you need to focus on simplier things

anywho, enough of the "hardass" talk, after all that (the same old same old) you should end up with the following:




ahh... almost done!
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Last edited by jlmakes : 01 January 2004 at 01:57 AM.
 
  11 November 2003
my contribution...

6) now, since we have the basic shape done... we'll add the rim of the wheel, and the "nub" as I call it. you basically want to create this shape of curve:



and after revolving and applying some surface fillet's between this new revolved surface and the extrusions of the inner spoke curves... you get this result.



(please keep in mind, I'm doine minor minor tweaks as I go, as to what looks best... for example, even tho I showed the above curve, I still pulled the bottom cv's down a bit so that it showed more through the spokes... that kind of stuff. It's really up to you to model this, I'm just helping you with the methods)

well...
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Last edited by jlmakes : 01 January 2004 at 01:58 AM.
 
  11 November 2003
my contribution...

7) seventh and final step, really isn't a step, its more of a conclusion type thing...

all you gotta do is just create a tire (revolved surface) and create the nub (lofted surface with a planar surface on the end circle) and add any details that you want (like the brake pads, and the calipers, bolts, etc...)

anywho, for this render, I just set up a simple dirtmap with Mental Ray and normal spotlight and this is what I got:



I honestly hope I didn't skip too many steps at the end there, I just figured that about ½ way through, you'd figured out the process... plus, I think did a pretty good step-by-step on the hard detailed parts. But regardless, if something is unclear, I'm here to answer your questions!!

Cheers!!

- Gremlin


edit: after further inspection, I see that my wheel isn't exactly accurate...but my reference wasn't very high res... sorry, I did the best that I could.
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Last edited by jlmakes : 01 January 2004 at 01:59 AM.
 
  11 November 2003
Quote: Originally posted by TheShaddix
THe question is: how to do it and what to use?
Ill be working on that area tomorrow, so stay tuned for updates.

In my experience the wheel well needs to be a trim, however for the front junction I would try to get the piece right out the birail operation (last cross section to a point), I know this generates a "three" sided patch but I made many tests and couldnt get it right with any other approach.

Gnz
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  11 November 2003
éej Gremlin!
awesome tut man! finally a really decent maya car tutorial! It's all about max here man! Not that it's bad, but I only use maya, a tried to get a grip of max, but it's another world compared to maya! Keep up te good work mate!!
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  11 November 2003
WHOA

this is a great tutorial man! yeah i've been having trouble trying to do cars and i'll follow this tutorial and post up one of me. keep up the good work and thanks.

your explanations are good and its easy to follow. the rims look sweet
 
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