The Desmos 3D Calculator allows you to explore points, functions, and surfaces with an interface similar to our 2D Graphing Calculator. As you start exploring, you’ll encounter the same expression list for typing your equations and many familiar settings. However, you’ll also discover some new options and extensions on previous features.
Getting Oriented
When working in 2D, your view is restricted to the \(xy\)-plane.
The
default view in our 3D calculator is a cube containing the \(x\)-,
\(y\)-,
and \(z\)-axes, you can view the same 2D plane by clicking
.
Plotting Points
One of the simplest things you can create in the calculator is a point. When working in 2D, points are plotted as coordinate pairs of \((x,y)\). You can still plot an \((x,y)\) point in the 3D calculator, and it will appear on the \(xy\)-plane. You can also add a \(z\)-component, with coordinates of the form \((x,y,z)\), to plot your point anywhere in 3D space. You can plot your points individually in an expression line, in the same line separated by commas, or with variables defined by tables, sliders, or lists.
Extending to 3D
In 2D, equations are defined with the variables \(x\) and \(y\). 3D enables you to work with expressions in \(x\), \(y\), and \(z\). If you type an expression in the 3D Calculator with only \(x\) and \(y\) variables, you will see your curve graphed flat on the \(xy\)-plane. You’ll also have the option to check Extend to 3D. By checking this box, the calculator will plot the entire surface of points that satisfies your expression for all \(z\) values.
You won’t see this checkbox if your expression includes a \(z\) variable.
Polygons and Triangles
It is often convenient to define a surface by points rather than an explicit equation. In 2D, you can use the polygon function to do this. In 3D, you can use the triangle function. To use the function, type triangle into an expression line. Or, click Show Keypad and then Functions. Then, scroll to the Geometry section and select Triangle.
However, the 2D polygon function can take any number of points, but the 3D triangle function can only accept three points as inputs.
Inequalities
In 2D, inequalities are essential for producing shaded regions on the plane, using lines or curves as boundaries. By using curly brackets, you can create a system of inequalities that restricts the \(x\) or \(y\) values. In 3D, you can extend this notation to create surfaces and solids by combining inequalities in \(x\), \(y\), and \(z\).
Parametrics
You can create parametric curves in 2D with an ordered pair where one or both coordinates are defined in terms of the parameter \(t\). In 3D, a similar approach gives you the option of creating parametric surfaces. To generate a surface, your expression should have three coordinates defined in terms of the parameters \(u\) and \(v\).
Learn More
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