Glass is an interesting material that will provide hours of fun (and possibly frustration) when trying to create it in 3D. Learning to create attractive glass textures will help you understand the Strata 3D texturing system, and avoid frustration.
We’ll explore the basics of creating glass in this short tutorial.
A very basic glass
Let’s begin by creating a new scene with the Tile platform preset.
Now, we’ll create a sphere, and we will use it to experiment with the texture settings.
Intuitively, a basic glass texture should be glossy and transparent, so let us do just that:
- Create a new Image texture
- Name it Base Glass
- Move the Glossiness slider to 100%
- Move the Transparency slider to 100%
The result is glossy and transparent, but lacks in “glassiness”.
There is a property of transparent surfaces called the Fresnel Effect. It has to do with how reflectivity depends on the angle at which light impacts the surface (mirages are due to this, by the way.)
The Strata 3D texturing system takes this property into account, and so, some modifications to our texture are required.
Double-click on the Base Glass texture. In the texture dialog, click on the arrow to the left of the Reflectivity category. A small dialog appears on the left side of the texture dialog. This dialog contains the more advanced texturing controls.
The default interpolator for new textures is None. Change this to Fresnel.
Do the same for the Embedded Reflection category, just below Reflectivity.
The rendered result is quite different.
Our next issue is that the glass we are creating is too transparent!
To bring the transparency down a bit, move the transparency slider in the texture to 95% and then set the Opacity slider to 10%.
Also, move the reflectivity to 60% (up from 35%) to compensate for the Fresnel interpolation that will result in less reflectivity almost everywhere in the object.
That’s our first, basic glass. At this point, a sphere is not complex enough to bring out the reflections, refraction and transparency we can get from Strata 3D. So, let’s make a wine glass.
About the models
The ideal object for experimenting with glass textures is a wine glass. We’ll draw a profile and then lathe it.
The idea is to create a thin wall of glass, thus enabling refraction and reflections in both inner and outer walls.
Here is the result:
Important points when modeling objects for glass textures are:
One sided
Make sure your model is one-sided. A one sided model is “solid” to the rendering engine, and refracts light realistically. If our model is two-sided it will look like a balloon or a soap bubble (useful to know when we are modeling ballons).
Below are the same glasses with the one-sided checkbox unchecked.
Avoid sharp edges
Sharp edges do not reflect any light back, and can make a model at best less interesting, and at worst confusing. Always try to add a bevel to edges, even a small bevel will do wonders.
Result
There we have it, a basic but beautiful glass texture.
There is a lot more you could do, playing with a glass texture – you could add tints, bumps, etc., but this is a good beginning.
