Research And Development Of Virtual Reality Experiment Platform For Engineering Graphics

Engineering graphics is a subject that studies the information expression,communication and transfer of engineering products,and is also the carrier of engineering and product information.As a basic course for mechanical and near-machine majors,the cultivation of students’ spatial logical thinking ability and three-dimensional modeling design ability is one of the teaching objectives and also one of the teaching pain points.The high simulation of virtual environment constructed by VR technology,the interaction between the user’s first-person perspective and 3d model of virtual space,and the breakthrough of being free from time and space constraints are very consistent with the need to create 3d learning environment for engineering graphics teaching.Especially in recent years,the online teaching caused by the epidemic makes the immersive VR teaching practice system come out.In terms of practicality and cost,this project uses skeleton skin animation as interactive mode and Unity 3D as engine to develop VR virtual experiment system platform.Determine the development goal of virtual disassembly system,summarize the development status of VR and bone animation at home and abroad,and build the development framework of the system.The assembly sequence,disassembly sequence and parts of the assembly to be disassembled are introduced in detail.Build the internal scene,external scene and sky box of the virtual reality platform and change the model material to increase the sense of immersion and reality.By using X-ray detection and collision detection technology;the human body model can interact with the parts by means of ray contact with the collider envelope.Design the basic UI framework,use keyframe animation technology to create working principle and explosion view animation.In the aspect of bone animation,the overall design framework of interaction mode is established,human skeleton is designed,linear skeleton skin algorithm is analyzed,skin weight is calculated based on it,and the character model is highly realistic.Study joint movement and skeleton kinematics,analyze human motion characteristics,analyze each frame of action posture,design interactive actions and control animation speed,Add FK controller,make walking,hand lifting,grasping animation and virtual scene interaction.Animation controller is used to combine it with Unity3D to complete the production of interactive mode.Finally,the character model can roam in the scene,and the engineering drawings of each assembly and part can be viewed in the scene and the interaction with other UI interfaces.In addition,the surface shader is added to realize that in the process of disassembly and assembly,the surface shader will produce the corresponding color change along with the correct disassembly and assembly to remind students to pay attention to the disassembly and assembly sequence.In the interaction with the parts,X-ray detection technology and collision detection technology are used to realize the disassembly and assembly of the assembly in the virtual scene,which verifies the feasibility of the combination of bone skin animation and virtual assembly.