A computer-implemented method for rendering physical behavior of a designed assembly of objects in a three-dimensional scene of a system of computer-aided design, the method comprising the steps of:
- providing the assembly of objects with information relative to kinematic joints linking objects of the assembly;
- providing a motion application tool embedded in the scene, said motion application tool being a graphical artifact presented on a graphical user interface as a representation of three-axes allowing for each axis a direction of motion in translation and a direction of motion in rotation, said motion application tool not belonging to the assembly of objects and said motion application tool being controllable by an input device of the system of computer-aided design;
- using said input device to attach said motion application tool to one object of the assembly and selecting a direction of motion using the motion application tool attached to the object of the assembly;
- using said input device or another input device of the system of computer-aided design for inputting at least one initial condition according to said selected direction of motion, the at least one initial condition including an initial speed or an initial acceleration of the object to which the motion application tool is attached, wherein inputting the at least one initial condition is executed by using said input device of the system of computer-aided design for imparting a movement to the motion application tool, the imparted movement to the motion application tool being converted to the at least one initial condition based on one or more measured values of a manipulation sequence performed by real-time user interactions with said input device or said another input device;
- and
- calculating and rendering on the graphical user interface in real time the physical behavior of the assembly of objects taking into account the at least one initial condition previously defined, resulting in a simulation of the assembly of objects;
- wherein the at least one initial condition is a computed average of the one or more measured values of the manipulation sequence.