Bryce

 Tutorial: Boolean Operations

 

Intersection Operations
Ok, imagine you need to hang some pictures. You need some nails for them and you have 2 jars of nails. One has 3 roofing nails which you can's use, and two 4d nails that you need.
Your second jar has four 4d nails you need and another roofing nail that you don't. If you dump them all together in one pile, the intersection of the two jars is six 4d nails and four roofing nails. Since you are interested in only the 4d nails, the intersection yields six usable nails and four roofing nails that you discard back to a jar.
This is the basic premise of an intersection boolean operation. One thing (your intersection object) is compared to another thing it overlaps (your positive object). The result is only where the two objects overlap. This operation is not used as often as the Negative boolean operation but performs some actions that would be difficult or impossible to achieve any other way.
Lets take a look at how we go about making a lense using two spheres and an intersetcion boolean operation.

First, we need two spheres. Here I have 2 shperes, one orange one green for this demonstration. I also gave the first sphere one of the glass materials from the library. You can pick one for yourself after you make your first sphere, but do it now so that material is used for the rest of the objects.

We will use the green sphere as our intersect, and the orange one as our positive. Notice that the green sphere is the exact same size as the orange one but is a little to the right. Its important to get this relationship. To do so, make your first sphere. Select it and hit CTL-D. This duplicates the sphere exactly. Now hold down CTL and ALT and drag the new spere right slightly.
With the green sphere (right) selected, click the chicklet as indicated here:

This brings up the Object Attributes window. Take a look around.

Note the boolean settings indicated by the red circle. We will be focusing on these settings in this tutorial. For now, leave everything else alone.

Select the " attribute.

Once you have the settings as they are to the right here, click the to return to the wireframe.

Now select the first sphere and set it to as indicated to the right here.

Once you have the settings as indicated here, click the to return to the wireframe.

Notice how there is no apparent change to the orange sphere but the green sphere is now all dotted. This indicates that the green sphere is set to intersect.

There is no obvious difference in the positive setting at this point.

Now, select BOTH spheres. Click the chicklet that appears when you have more than one object selected. This forms a group. Since we have set objects with boolean attributes, Bryce automatically forms a boolean group as indicated by the corner lines of the group bounding box. This is indicated by the yellow circle in the image to the right.

If you DO NOT have these corners, you did something wrong, go back and check your settings for each object and attempt the grouping again.

Here is the resulting render from two different angles. The first is the same as the wireframe views above, the one on the right is more from a 45° angle off to the side.

Notice how the negative sphere (green) and the positive sphere (orange) both are not visible. The only remaining visible portion is where the two spheres actually overlapped each other

This is the simplest form of a intersection boolean operation, two objects, one operation. The operation can be complex where there are multiple objects within the same group acting upon each other. Until you are confident of your results, you are better off sticking with simple groups.

Here you can see an overlay of the wireframe on top of the second render as seen on the right above. You can clearly see that the lense is formed only where the two spheres overlap.