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Creating cogs in bryce

Author: xalthorn

Tools Needed

  • Bryce

Introduction

Creating objects using basic shapes in Bryce can give some great results but may seem daunting at first.

I'll try to show how relatively simple shapes can be created fairly quickly with a few of the inbuilt tools in Bryce.

In this example, you'll see how to create a basic cog shape.

Step 1 - The main cylinder

The first thing we'll create is the main part of the cog wheel.

This part is a simple flat disk, or cylinder.

To create it, create a new cylinder object from the toolbar at the top of the interface. It's in there with the sphere, torus, cube, etc.

Once you have the cylinder in the scene, click on the 'A' in the vertical set of icons that appear next to it whilst it's selected.

This will bring up the object attributes window. Set the various values as shown below:

The positive option should be selected

origin 0, 0, 0

position 0, 0, 0

rotate 0, 0, 0

size 100, 10, 100

400-0270.jpg

Step 2 - The first tooth

The next thing to do is to position the first of the cogs teeth. This time we'll be using a cube.

Place a cube in the scene, make sure it is selected and click on the 'A' just as before.

Before we start setting values, we need to click on the padlock between the Origin and Position rows. This allows them to have different values rather than being the same all of the time.

Now we can set the various values as shown below:

positive should be set

origin 0, 0, 0

position 0, 0, 52

rotate 0, 0, 0

size 10, 10, 10

400-0271.jpg

Step 3 - The rest of the teeth

Rather than try to position and rotate the teeth by hand, we can use a neat little trick that Bryce has to do it for us.

With only the cube selected, we need to click on the Edit menu and select the Multi Replicate option. This brings up a little window with more options to fill in.

Fill in the following values:

quantity 17

offset 0, 0, 0

rotate 0, 20, 0

size 100, 100, 100

When you click on the tick, you will suddenly have 17 more teeth around the cog.

The reason this worked so well is because we set the first tooth to be positioned at the edge of the cog, but have it's origin (or centre of rotation) at the centre of the cog. This means that when we replicated it, each cog moved around the edge of the cog nice and neatly.

The reason we have 17 replications at 20 degrees each time is because there are 360 degrees in a circle, we are stepping forward 20 degrees each time which means we want 18 (360/20=18) teeth, but of course we already have the first one.

400-0272.jpg

Step 4 - Put the hole in

The next thing to do is punch a hole in the centre of the cog.

We do this by adding another cylinder to the scene, selecting it and clicking on the 'A' as before to set it's various attributes.

The values should be as follows:

negative should be selected

origin 0, 0, 0

position 0, 0, 0

rotate 0, 0, 0

size 20, 12, 20

The reason that this cylinder is negative rather than positive is because we want to use it to cut a hole in the overall shape.

When you group objects together, which is what we'll be doing in a little while, all of the objects that are set as positive will be in the final shape whilst objects that are set as negative will cut their shape out of the overall object.

The more astute will also notice that the hole is slightly larger in the Y axis than the rest of the shape. This is because if it was the same size, it may not cut all the way through the object.

Anyway, we need to group all of this lot together.

Start by selecting one of the objects. To add another object to your selection, hold the shift key down and click on another object. Keep doing this until you have selected everything.

You will probably find that it is hard to select an object that is overlapping one or more other objects (the hole for example). If this is the case, hold the control key down as well as the shift key and when you click, you will be given a list of possible objects that could be selected.

Once everything is selected, a 'G' appears in the vertical list of icons next to the selected objects. Clicking on this will cause the whole lot to be grouped and make the positive and negative objects work together.

400-0273.jpg

Step 5 - Texture the thing

That's it. You can now texture the new combined object with one texture (click on the 'M' in the vertical list of icons to enter the texture screen).

Have fun and try out different things.

As a point of interest, if when you apply a texture to the group, the main cylinder appears to be different to the teeth, try changing the texture mapping mode to 'World Space'. The texture mapping mode can be changed by clicking on the text that will say something like 'Object Space', 'Parametric', 'Spherical' or a whole host of other variations underneath the colourful textures on the right hand side of the texture screen.

400-0274.jpg