Cinema 4D - Gears - Methods, Options and Observations.

My first attempt at modeling a gear in Cinema 4D R13 was a concave helix gear I believe they are called, shown below.

When I first rendered them out I was pretty proud and it isn't a "bad" render. But there are some mistakes I made during the modeling process that effected the render, things I will point out later in this post that needed attention.

Let me state, I'm not going to teach you how to create gears in Cinema 4D. I'm not a modeler by any means and wouldn't feel comfortable doing so. Nor am I one that is going to parrot others like I know what I'm talking about or it's something I came up with. Unless it's an AR Drone Parrot - Parroting is not my style.

What I am going to do is give you some of the direction, as I found, when attempting to create gears for the first time in Cinema 4D. As well as some personal observations and tips if you will of things I made while making my gears. All on one page. This page... ;0)

On to the task at hand... here are some options, methods and tools.

1) Use some one else's gear model(s) - A viable solution if you are not into modeling them yourself. A lot of people do just that. You can do a search via Google and find a ton of them at just about every 3D model host or supplier. Some are free and some cost. Many are cross platform some are not so be sure to check. And download the correct format you desire.

A quick search of 3D CAD Browser and here is a set of Gear Wheels

2) Plugins for Rigging - While on the note of using someone else's work. For rigging and more...

Here is a free Xpresso Gear Rig from Pixel Lab by Ryan Gibson for as well..

And there is also Xtreme Gear found over at C4DZone.com

3) Use a Gear Calculator - If you want your gears to mesh together you might want to make use of a gear calculator.

Over at CG Society Bjorn Marl (Srek) stated the following:

This is less of a modeling than an algorithmic question.
Personally I use this for my needs regarding simple, working gears.
http://joostn.github.com/OpenJsCad/gearsdemo.html

And Sébastien Florand (fluffouille) as well offered up the following:

That is where math comes in, it has nothing to do with modeling techniques (which are quite simple, since most of these gears can be made with simple Loft NURBS).

Since teeth sizes need to match up between each set of gears, you need to know how many teeth you'll need for any given cog size.
Here is a calculator that will help you define the diameter of each cog for a specific number of teeth (using standard teeth sizes), and the distance needed between each cog to make them match.
Note that this one only applies to spur gears: http://www.ultrascale.com/node/15
Here is another calculator for helical gears: http://www.mesys.ch/calc/helicalgear.fcgi And here is a page I found via Google that simple explain how to determine Gear Ratio's
WikiHow - Determine Gear Ratios

And for those that want the deep math on determining Gear Ratios:
(SCHSM) Sothern California Home Shop Machinist - Gear Ratio Calculations

To make better use of the gear calculators you might want to know the parts of a gear and gear types so here are some reference images and links to help you out:

Wikipidia image Gear Tooth Terms

Gear Terms

Robotic Mechanics- All types of Gears 51034

Gears and Stuff - Types of Gears

ConeDrive Double-Enveloping Worm Gears

ZakGear - Ultra Globoidial Gear (UGG) Advantages - (more on the  Condrive gear with animation)

4) Model your own. - This is what I wanted to do. There are several methods to model a gear in Cinema 4D. I'll go over a few that I know about.

4A) The Cog Tool and Loft - Cinema 4D has a cog tool to create gears and more. If you knew that, great! If not, you do now. It's in the Spline creation menu. And great for making gears.

Personally, I had no idea C4D had a Cog tool when I modeled my first gear. I searched the help for gear and nothing came up. Searched the web and again nothing about it. And no one mentioned it in the forums. They probably thought I already knew about. I didn't find out till a week later when doing something else.

And now that you do know about the Cog tool, lets take a look at the suggested method of modeling a gear using the Cog tool with the Loft tool as mentioned by Sébastien above.

When using the Loft tool you'll need at least two Cog splines. I'm going to use the default cog spline. Lets take a look at the result.

I used a subdivision of between 150 and 300. And no matter a lot of triangulation is going on. You can play with the subdivisions and try to get the best results. I used Linear as well. Minimum subdivisions on the Z or X is 2.

The mesh is a mess, but don't fret. The Loft tool still can be used. Just in a different way. And here is the result with a good clean mesh.

Loft B - Its done by selecting "Loop". You'll get just the outer most poly's, a outer loop if you will. You'll then have to boole in the center and close each cog tooth with the close poly tool. And the resulting render:

Using method Loft B the render is clean with no artifacts.

After reading other methods, don't be quick to discount this method out, you can get some pretty cool meshes and rings from the Loft and cog tool combination. Depending on the gear or other things you are making this is a very valuable tool and method to use.

Created using Cog, Loft, Extrude and Close Poly tools.

4B) Cog Tool and Extrude - Another method using the cog spline tool is to use the extrude tool. This resulted in a very clean low poly mesh.

Cog spline extruded.

Cog spline extruded and booled.

Again you can end up with a mesh that is messy when booleing in other parts. But there are ways to eliminate that in Boolean tool. Here is comes one...

Tip: Not to necessary to use all the time but if you having trouble, try checking off "Hide new edges" in the Boole tool. You're meshes may be cleaner.

Using Cog tool with Extrude on a 33 degree helix

4C) The Array Method - This is the way I first learned to make a gear and the method I used to create my first gear render in the beginning of the post. And I modified even this method to suit my needs, but is one method that I drew a lot knowledge from by Murder Toys on Youtube.

Now if you are going to use this method you'll also want to check out some info on the tools used in Cinema 4D for this such as:

The Boolean Tips for Cinema 4D by Jamie Hamel-Smith

When I did this method I was creating a different style gear. I did not use a few of the tools he uses like the taper tool or Hyper Nurbs. I did loop select edges and add a bevel before adding to the Array.

TIP:  If you are going to loop select the cog edges and bevel them only. You need to do so on the back side or if you did them on the front side, change the axis of the cog or the bevel side will be facing towards the center of the Array. Rotating the mesh doesn't or didn't do anything to change this. 

What I found was if the cogs are protruding - I was getting artifacts when rendering. I couldn't see them in the mesh. But they showed up during rendering. You can see them around the center circles. Little flicks. I take it they are from the triangulation of poly's that occurs when booleaning the objects. So keep in mind what I stated earlier about hiding new edges when booleing if necessary. 

That stated, I also have been having some serious issues with my comp since attempting an install of Net framework  3. Its showing up when rendering projects both in AE and now C4D. And also while modeling the projects. Really strange things going on. So I'm not ready to put it all on C4D or how I modeled it.

TIP: If you find you have a lot of triangles - you can try the Un Triangulate. But be carefull, you may find you lost poly faces. Check the whole object over before continuing or be prepared to fix the mesh.

And here is the mesh of my Concave Helix using a modified Array method:

4D) Use the Cloner - Keeping in line with the Array Method in the previous tutorial, try using the Cloner.

Here  is an example of a simple gear using the Cloner after booleing.

You'll notice I wanted a cut between cogs, for 18 cogs I used 18 subdivisions and rotated it till it centered each cog.

And another similiar to the Helix I made with the Array method.

For this style I used the Shear Deformer on the Cog before using the Clone tool or boole union. I was intending to do another type gear, hence you see so many subdivisions in the mesh. It's still a clean mesh as you can see below.

Don't be afraid to use Photo techniques when setting up your rendering.
C4D High Key render.
No HDR, GI or AO used
No Post Processing.
Native C4D 8 bit jpeg output

4E) Front Profile method - If using the Cinema 4D Cog tool is a side profile then I guess this would be a Front profile method. This is a lot of modeling so be prepared, though it is really good to learn this method. Keep in mind while following this tutorial, there are still more methods to this method but I'm not going to get into them here. 

The tutor in the following tutorial is using the "Front Profile" method to make a tire and early on I'm sure you can see, as I could, that it can be used for creating a gear amoung other things. And though this tutorial is not in English. You can follow it a long pretty easily or try an online translator for the page. You are simply making a front profile of the gear. A bit of modeling as stated, you'll see.

Einen Autoreifen erstellen

5) Learn about reflective materials, metal materials, GI and HDR. - These are essential to create a descent render. For instance take anther  gander at my first render:

Now take a look at it once I gave the Chrome and other polished metals something to reflect:

Looks a little more like you expect chrome to look. Now I really didn't care abou this particular rendering as my interest was simply to show the gears and have a preset of them for my self. But, didn't want to leave anyone that might see this post wondering why they're chrome looks all grey or washed out.

GreyScale Gorrilla stated it best - You need to give reflective surfaces, chrome, polished metals etc etc, something to reflect. If there is nothing in the scene, then there is nothing to reflect.

Here is a tutorial he did that I'd recommend you watch that goes into much of this:

Springs, Coils, and Bolts – Replicating a 3D Max Render in Cinema 4D

Having fun with reflections.
If you watched the GSG Springs tutorial you'll get the joke.
What's real and not real in the reflection?
You decide.
(And no, that's not me behind the camera.)

Also look up any improvements they have made in GI, Physical, AO render settings for your version of Cinema 4D. I'm using R13 still, and I know they have made improvements in both R14 and R15.

6) HDR and Bit Depth. In my opinion and for me personally using HDR  is not necessary for every single render. Especially if you know you are going to only be rendering an 8 bit jpeg as I did with the above image. HDR does make a huge difference. So does going 16 - 24 or 32 bit. A tremendous difference. So use it wisely.

But do what you feel is best for your render and application. And do yourself a favor and read up on what they are. And that you can do at the following places:

FAQ - HDR images for Photography

7) Putting it all together - There are a lot of variables, various methods and you must descide what is best suited for your particular need. Experiment and try different methods for each type of gear and sinerio. Keep in mind what you are doing with the gear(s) you are making. Do you need low or high poly counts, do they need to mesh together, are you going to 3D print it out, etc etc.

I don't have all the answers nor am  I fluent in all the techniques myself, but hope I helped give you some solid direction so you can create your own gears. Or even when using others gear models. In the near future, I'll be adding more about worm gears.

And what should you do if you find out after all your work you screwed up when making your gear model? Well don't stress about it, till you make another one, you can turn the one you messed up into an ashtray or perhaps do like I did. Turn it into a frozen Ice sculpture Punch Bowl, model a couple glasses, fill it with your favorite beverage or liquor, take a deep breath, call your loved one over so you can share it and get geared up for the Holidays with some cheer.

Till next time - Happy Holidays.
and keep rendering.

- chase -