Plasticity is an in development 3D modelling application based around NURBS or Non-Uniform Rational B-Splines. NURBS is a mathematical way of describing smooth surfaces using shapes built of curves and was a popular way to model organic shapes. Plasticity uses NURBS curves and shapes in an attempt to create a more clay-like modelling experience.
Plasticity is described as:
Plasticity is a 3d modelling software for concept artists. Modeling in Plasticity is quick and efficient due to the unique gizmos, shortcuts, and thoughtful workflow.
The goal of plasticity is to make working with NURBS like working with clay.
Plasticity is mostly Open Source. When Plasticity reaches 1.0, it will cost $25 to use (no subscription).
Plasticity is currently in the early stages of development with many more features to add and bugs to resolve. The project is currently in need of Beta Testers who can find and report bugs.
Plasticity is partially open source and hosted on GitHub under the LGPL v3 license. It is currently free to download and use, but upon reaching 1.0 release will have a price tag attached. If you are interested in learning how to use Plasticity the author has a series of tutorials available on their YouTube channel. Of course you can also see the Plasticity NURBS based modelling application in action in the video below.