How to Model a Glass Containing Liquid

This tutorial will show you how to put liquid in a glass. Use the techniques here to put a liquid in your own glasses, bottles, buckets, etc.

First create a glass. For this tutorial, I am going to use a simple cylinder. However as you learn to use the Bryce interface, you can create complex glasses to put your liquids in. So create a cylinder and size it to suit your needs.

Make this cylinder positive by selecting the "A" out from it and choosing "positive" from the menu.

Next duplicate this cylinder by using the menu’s edit/duplicate command.

You will now have two cylinders. Make the duplicate smaller than the original by dragging the resize control in the edit tab.

Resize again by dragging the top of the resize control to make it extend out of the first cylinder.

Now make this cylinder negative by selecting the "A" and choosing "Negative" from the menu.

With your mouse drag a marquis around the two cylinders to select them both. Once selected click the "G" to group the two cylinders. If you look in your preview window, you will see that the negative cylinder cut out the positive cylinder to form a glass shape.

Now it’s time to put the materials on your glass. Click the "M" next to the group and select the triangle next to the preview window (indicated by the #1 in the picture). Next select the Glass textures by clicking the glass materials in the presets (indicated by the #2 in the picture). Now select a suitable glass material (indicated by the #3 in the picture).

You now have made your glass. It’s time to put some liquid in it. So you must select the inside cylinder (the one you last created). How do you do this now that it’s inside a group? Easy just hold your mouse over the cylinder selection control (at the bottom of the screen) and press. Hold the mouse button down until you have a popup appear that lists all the cylinders in your scene. Select the second one.

To view the selection palette, click the icon in the lower right corner of the screen.   This will alternate between the timeline and the selection control palette.

Tada! Now your interior cylinder is selected.

It’s now necessary to duplicate the cylinder to create the liquid. So just follow the steps you did before. Go to Edit/Duplicate in the edit menu.

If you remember, the second cylinder was set to "Negative" earlier. This duplicate is an exact replica of that one. For the liquid to show, this new object will need to be a positive so you must now make it positive by using the same method you did before. Select the "A" and then click "Positive" to change this third water cylinder.

It’s now time to resize the liquid so that it isn’t all the way to the top, so select the resize control in the edit tab and drag the top of the control to decrease the size of the liquid.

Now it’s time to put a water material on your new cylinder. After all it is water or some other liquid so click the "M" just like you did before. Next select the small triangle next to the preview window (represented by #1 in the picture). Now select the Water pre-sets by clicking (represented by the #2 in the picture). After doing this choose an appropriate liquid (represented by the #3 in the picture).

Once you understand more about the material editor, you can change the attribute of your liquid to make it a different color or even a different material (sand or some other solid material). You might find a pre-set material you like better than the one I have chosen here.

This next part requires you to think a little. The duplicate you created to make the water is part of the boolean group that created the glass right? This duplicate is also the same size as the negative that cut out the interior of the glass. Boolean operations will cut out a positive object in a group right? So if you render it now, the water wont show. Got to fix that right? So it’s necessary to separate the water from the glass then put it back. How do you do this? Several ways, but here is the easiest.

Select "Cut" from the edit menu. This will cut your water cylinder not only from the scene, but also from the group it’s currently in.

Now to put it back in exactly the same place with the same material, simply select paste from the edit menu.

You can now render your glass. It will contain the liquid you wanted it to have.

There are lots of ways to put liquid (or some other material) in a glass but I think this is the fastest once you learn the interface. This tutorial was designed to help you learn not only how to make the liquid in a glass, but also to help you use the interface!

Hope this helped you.


Occasionally you may encounter a problem using this method. Notice in the image that the surface of the liquid renders quite clearly, but the base of the liquid is invisible or broken up.

I can not consistently reproduce this error, but I can offer a workaround IF you happen to have this problem in any image.

If you notice this appears to be related to the change in material at the interior surface of the glass object and the exterior surface of the liquid object. In effect, Bryce is trying to change materials in exactly the same 3D coordinates. It appears that Bryce is getting confused.

To fix this problem, simply select your liquid object and enlarge it very slightly. This will cause the material conflicts in 3D space to be removed because the interior surface of the glass object and the exterior surface of the liquid object are now in different 3D coordinates.

Tada, the problem is gone and the semi-transparent wine and the smooth solid milk render quite nicely!