I scanned a gear at 600 dpi, adjusted contrast in Photoshop, selected the white area, then created a work path. I exported that as path.ai, and used it as the cross-section of a spline object (a gear) in Carrara. As you can see in the above image, the results are poor, regardless of whatever smoothing or tolerance I used in Photoshop. Is there a way of generating gears with a good tooth shape and specific number of teeth, in such a way that they are much more mathematically perfect than the above?

You really need to create paths ina vector program such as Illustrator or Corel and export them. Creating paths in photoshop from a scan is not very accurate as you have found out.

if you have illustrator you have a function called trace(i think),so you can bring a image into illustrator and trace it and you have the gear ready to export it and import it into carraras spline modeler.
or make it in illustrator without tracing the image and export it,sometimes the trace function is not very accurate.
btw. real-draw pro works good for me.

Message edited on: 08/12/2004 00:50

Not exactly a technique for making gears, but a good source of ready made ones- Somebody made a gear font which you can use with the CS text tool to make a set of gears- I don't know where to find it though. . . anyone? Try asking over on the yahoo group if nobody here has it, I'm sure someone there does. Markd

doesnt digital carvers guild have a plug in to create gears and machinery?

I believe Eric has a plug-in that will work, and there's also a tutorial (for sale) on how to draw gears in Corel or similar. However, I'm hesitating on those, since I don't know if they allow a very specific tooth shape. Apparently modern self-lubricating gears have an elegant, non-intuitive tooth shape that makes for efficient engagement, low-friction force transferral, and disengagement. I have a feeling Photoshop will work, but it's a matter of getting all the teeth to be identical (and correctly spaced) that precludes a tracing operation (or any non-mathematical solution).

Eric has a plugin for the PHYSICS of gears. As in, apply the plugin and tell it which gear is what in the chain, whats tha axle, etc, etc, etc... I don't beleive it MAKES gears.

Make gears not war

There was a freeware program I got awhile back called gearmaker. You set all the gear parameters and it made an OBJ file. Works great for gears. I have just had a look and it is in the free section here at Renderosity Cheers Neil

have you tried increasing the surface fidelity in the spline modeller?

How to make a perfect gear with Adobe Illustrator This is using the Mac * In Illustrator draw the circle of the gear. Mark the center with guides. * Draw the tooth of the gear. * Place gear, overlapping the edge of the circle a little. * While the tooth is selected Press R and place the rotation center point at the center of the circle. Click the center while holding down the option key. * In the Rotation dialog box put in the degrees of Rotation. 10 degrees for 36 teeth. Click copy * This rotates a copy of the gear. * On the Mac press command/apple D to duplicate the last action. A new tooth is created and rotated on the circle. Keep pressing command D until all teeth are placed. * Select all the teeth and circle and using the Pathfinder palette, click on first icon in the upper left. It looks like 2 squares merged. On Illustrator 10 and CS press EXPAND after. * Now you have a perfect gear that can be saved as Illustrator 8 and bellow to use as a template in Carrara

Yes, Notefinger, that should work. I did the analogous operation using Photoshop's Path/edit functions (see above image), but Illustrator is better. Tempest, I increased spline geometry/resolution to 1000% or 400%, but it didn't make any difference. Neil, I'll check for gearmaker - hey, it's by one of my old pals, kawecki, but PC-only 8-(

There's a free version of Cinema 4D called Cinema 4D CE 6, which includes a gear tool that works very nicely. You can change the parameters of the gear any time after you've created it. The only thing is, I don't know how you can get this program. I got it from a CD that came with MacAddict magazine, and I've seen it on CDs from other Mac and PC magazines. It's certainly worth the cost of a magazine for all of the fine modeling tools.

Yes, renderer - that looks like a very useful tool. I'll check into it. Perhaps there's even some hope that Eovia will add such tools to Carrara. My initial assumption was that generating gears in the spline modeller would be so trivial that Eovia didn't feel it was necessary to add a module for that purpose, but now it seems that third-party software is required if we want to render gears in Carrara.

I dont know if this is what you are looking for...but you can just use the vertex room to build some vary vary fast gears.....just use an ovel add thickness then flaten and then extrude....it is a very easy way to make gears in carrara. kirk saavedra

Whenever I've done gears, I always make the hub separate and add the teeth as separate objects. Given I know how many degrees are in a circle, I can specifiy the exact number of teeth. This also works when I want two gears with different sizes but have the same sized teeth (my bike as an example). Sounds like a tutorial. -Kix

-Kix

a tutorial would be cool,very cool.i always make gears in real draw pro cause i dont have illustrator.i never did a gear in photoshop but i think i have to try this and also making a gear in the vertex modeler or in amapi pro.:)

Yeah, Kix, I'd like to see a tutorial on this. I can see how extrude would work in vertex modeller, but not how we could extrude a specific tooth shape, as opposed to a simple trapezoidal tooth, like on a sprocket.

This is a still from an animation I did for work. The gears were built in the spline room and are several pieces -- each tooth is rotated and duplicated around the outside of the disk it's mounted on. The disk has the ridges and the center pin, too. The center pin doesn't rotate, but the disk does.

Rotations of the gears was pretty simple to calculate based on the number of teeth and the rotational speed I wanted to convey. It's a pretty detailed animation; I'll try to post it at my home site tonight....

just use amapi a circle and the "alternate" selection mode which will select alternate vertices and extrude you can do that with the free amapi that comes with carrara. :) BT