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Arenyth
08-24-2006, 06:40 PM
Hey,
I'm working on an animation involving a CNC machine, or at least the drill going across the metal. But I can't figure out for the life of me how to model a drill bit. All that curvy-ness going down... it gives me a headache. Can anyone help? Obviously the bit will be spinning fast, but I can't just have a cylinder, it looks so fake. Does anyone know of a tutorial or anything? I find it hard to believe no one has ever modeled a drill bit before, but I can't find anything.

Thanks for your help

saltydogdesign
08-24-2006, 07:31 PM
You could approach this a couple ways: either make a spiral tube and use a boolean to remove it from a cylinder, or you could extrude a drill bit profile and twist it. Which you prefer depends largely on what modeling package you are using, though the latter method would definitely give you better control.

Arenyth
08-24-2006, 07:35 PM
I'm using Maya7, and I friggin hate booleans. I can't ever get them to work properly. Either it does nothing or it makes the whole object disappear. I'm not sure what a drill bit profile is, could you explain? Is it possible with maya?

saltydogdesign
08-24-2006, 08:12 PM
Yeah, booleans can be kind of a drag. Anyway, by "profile" I mean like a cross-section. When you stop and think about it, a drill bit is really just a rectangular strip of metal that's been twisted a few times. Well, really the sides of the profile are usually concave, but that's the idea. See the attached image for my top-of-the-brain idea of what the profile probably is.

I'm sure this can be done in Maya, but I couldn't tell you how. I'm a modo/LW person.

locke2121
08-25-2006, 12:54 AM
This is what happens. This is a fast and dirty model I did in about three minutes, so it doesn't look polished, but here is the idea. Create a rectangular spline, pinch in the long sides a bit, select it and extrude upwards a bit, then rotate the top a bit, extrude a bit, rotate, extrude over and over again till you get the size you want. The tip is easy, just close off the model, connect the pinched areas with a line and lift it up a touch.

4 low
08-25-2006, 04:18 AM
I modeled a drill bit once that came out pretty nice, too bad it ended up getting cut from the animation... but that's how it goes.

Anyway, I don't know much about Maya, so hopefully you can understand what I'm getting at.

But basically I drew out a spline shape that matched the cross-section of a bit. It's basically a circle, with two C shapes cut out at 180* of each other. It would be similar to the one posted above, but with rounded sides, instead of square. When you leave them square like that, it looks more like a DNA helix than a drill bit, and since drill bits are round, those edges should be round also.

I then extruded that shape down, adding several segments along the way. Then I applied a twist modifier (not sure what the maya workflow would be) and twisted it until it looked like a drill bit. I then tapered the end down to a point. Apply a meshsmooth or turbosmooth or whatever maya has and adjust accordingly.

I applied a dark gray material to the "cutout" portion of the bit, and a shiny metallic material to the outter portions, and that was all it needed as far as materials go.

Done and done.

locke2121
08-25-2006, 12:51 PM
Yeah, the concave curves work alot better.

saltydogdesign
08-25-2006, 02:09 PM
I cooked up a little animated gif showing how I'd do it in modo. I took most of the interface elements out so that they don't confuse, except in places where they help illustrate a point. How you get from one step to the next will vary depending on your modeling package.

IMO, this is the best way to approach this problem. If you know the drill bit is supposed to be three inches long, you can start with a three-inch long box. You wind up with a nice, smooth mesh, not too many pixels. You can control the ratio of turns to length perfectly. This is pretty similar to the method by which drill bits are actually manufactured, though whether that is an advantage or not I'll leave to the reader.

If I were moving ahead with this, I'd apply weight maps to the edges to sharpen them up -- right now it's like a Fischer-Price drill. But anyway, here's the technique...

http://saltydogdesign.com/cgtalk/drillbit.gif

Also good for making rotini.

4 low
08-26-2006, 06:24 AM
Here's my method, using 3ds Max:

Start with a basic spline shape:

http://img223.imageshack.us/img223/473/splineshapehl2.jpg (http://imageshack.us)


Extrude to desired length, and add plenty of segments:

http://img223.imageshack.us/img223/7362/extrudeuh8.jpg (http://imageshack.us)


Twist until you get something that looks good:

http://img242.imageshack.us/img242/295/twistlu9.jpg (http://imageshack.us)


Taper one end to a point:

http://img209.imageshack.us/img209/7151/tapergb7.jpg (http://imageshack.us)


Apply some materials, set up some lighting and a camera, and push render:

http://img242.imageshack.us/img242/6908/setupll9.jpg (http://imageshack.us)


Rendered image:

http://img209.imageshack.us/img209/1926/renderpp2.jpg (http://imageshack.us)


Total time for everything, including posting this reply and uploading pics--less than 10 minutes.

Arenyth
08-26-2006, 04:28 PM
Wow guys, you have no idea how much this means to me that you went through this effort. This is all perfect! I love you guys, although now I'm a little upset that my hours of confusion in front of the screen could have been done in ten minutes :P
But thank you thank you thank you! This is awesome!

locke2121
08-26-2006, 08:10 PM
Don't be upset...sometimes the answer to a question is so simple we fly right past it.

Pixaloop
08-28-2006, 08:38 PM
Wow..incredible response. I was thinking way too hard..hehe. The answer seems so simple, it makes me chuckle. My problem is "thinking 3d"...the beginner in me.

Well done 4 low!! :applause:

Arenyth
08-29-2006, 01:21 AM
. ugh, ok. It seemed easy enough, except that I have no twist tool in Maya. So I still can't get anything to work. Can anyone show me this in maya? I try to twist it after extracting, but I can only use rotate and it doesn't look anything like it.

Bahhh help!

4 low
08-29-2006, 03:24 AM
. ugh, ok. It seemed easy enough, except that I have no twist tool in Maya. So I still can't get anything to work. Can anyone show me this in maya? I try to twist it after extracting, but I can only use rotate and it doesn't look anything like it.

Bahhh help!


I know this won't help you figure out how to do it in Maya, but if you're in a bind and really need the piece, I can get you an .obj or .fbx if you want it.

kirigoi
08-30-2006, 12:26 AM
I'm only just starting out in Maya, so there might be a better way. In the Animation menu set, select Deform->Create Nonlinear->Twist :)

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