  3D modeling of biological structures is an inherently complex process,
necessitating both biological and geometric understanding. Additionally, the
complexity of user interfaces of 3D modeling tools and the associated steep
learning curve further exacerbate the difficulty of authoring a 3D model. In
this paper, we introduce a novel framework to address the challenge of using 3D
modeling software by converting users' textual inputs into modeling actions
within an interactive procedural modeling system. The framework incorporates a
code generator of a novel code format and a corresponding code interpreter. The
major technical innovation includes the user-refinement mechanism that captures
the degree of user dissatisfaction with the modeling outcome, offers an
interactive revision, and leverages this feedback for future improved 3D
modeling. This entire framework is powered by large language models and
eliminates the need for a traditional training process. We develop a prototype
tool named Chat Modeling, offering both automatic and step-by-step 3D modeling
approaches. Our evaluation of the framework with structural biologists
highlights the potential of our approach being utilized in their scientific
workflows. All supplemental materials are available at https://osf.io/x4qb7/.
