Real-Time Optimization PDF

Real-Time Optimization 3D Modelling Games and Multimedia Author: Alexandrino Gonçalves Last revision: 25/11/2024  Real-Time Rendering Gaming is probably the area that take most advantage of real-time rendering For that, gaming requir...

Real-Time Optimization 3D Modelling Games and Multimedia Author: Alexandrino Gonçalves Last revision: 25/11/2024  Real-Time Rendering Gaming is probably the area that take most advantage of real-time rendering For that, gaming require an approach to 3D modelling for real time that emphasizes efficiency and portability Despite the (hardware) technological advancements (more memory, faster CPUs and GPUs, etc.), there is always a limit to what the hardware can achieve For that reason, it is of paramount importance to optimize our project for real-time rendering 3DM 2  Number of Polygons The first optimization rule you must keep in mind when modelling 3D scenes, is to keep the number of polygons down (check the requirements of the Practical Evaluation) But the realism of a 3D scene is directly proportional to the number of polygons used to model it This issue is particularly important in real-time rendering The purpose of most optimization techniques is to increase realism without increasing, in the same proportion, the number of polygons of the objects in a modelled scene 3DM 3  Number of Polygons Carsoscópio: Geodromo (vegetation) 3DM 4  Number of Polygons Use all optimization features of your 3D modelling software. Blender has the modifier Decimate to reduce the vertex/face count with minimal shape changes 3DM 5  Number of Polygons Use all optimization features of your 3D modelling software. The following example used a modifier of 3DS Max Without optimize: 413 973 polygons With optimize: 85 143 polygons 3DM 6  Level of Detail (LOD) Level of Detail (also known as LOD), refers the ability to decrease the complexity of a 3D model according to the distance from the viewer or to other metric such as object importance, viewpoint-relative speed or position 3DM 7 Level of Detail (LOD) 3DM 8  Level of Detail (LOD) Sometimes the minimum distance is configurable 3DM 9 Level of Detail (LOD) 3DM 10  Level of Detail (LOD) This concept can also be applied to textures (e.g. mipmaps) 3DM 11  Culling Culling is the process to selectively disable the visualization of 3D elements in a scene. This procedure is applied in: Visibility within the viewport (frustum culling) Orientation (back-face culling) Hidden surface removal (occlusion culling) 3DM 12  Frustum Culling Only the 3D entities inside a defined viewing volume are rendered for visualization. To improve this procedure an adequate hierarchy of the objects in the scene is of paramount http://karolyszanto.ro/MastersThesis/presentation/assets/view_frustum.png importance Alexandrino Gonçalves Alexandrino Gonçalves Alexandrino Gonçalves Alexandrino Gonçalves Alexandrino Gonçalves Alexandrino Gonçalves 3DM 13  Back-Face Culling Back-face culling determines whether a polygon of a graphical object is potentially visible For optimization purposes, normally only one side (face) of a 3D object can be drawn in a virtual environment 3DM 14  Cloning Cloning (also known as instantiation) is the reuse of the same geometry in different locations of the scene To the cloned objects it is possible to apply geometric transformations without affecting the original object. These geometric transformations are: Translation Rotation Scaling 3DM 15 Cloning 3DM 16  Billboards Billboards are geometric entities that are always facing the avatar This can have great impact in optimizing a virtual world since we can use a simple plane (1 quad/2 triangles) with a texture applied to simulate complex geometric objects, while maintaining an apparent 3D appearance Most suitable for surfaces with geometric symmetry 3DM 17  Billboards For example, the columns of the virtual reconstruction of the Flavian Forum of Conimbriga were obtained with a half-cut cylinder billboard with a texture applied 3DM 18  Export 3D Scenes You must be aware that when exporting a 3D file between software applications, they do not come optimized and any optimization techniques you might have applied can be withdrawn. For example: Cloned objects can be replaced by real geometry Incorrect exportation of the polygon normal, which led to subsequent flaws in the (illumination) rendering (holes, for example) 3DM 19  Textures Textures can have a massive role in optimizing for real-time rendering For optimization purposes you should consider: Small images (in resolution) – Smaller file sizes uses less memory Use power of 2 (2n) resolutions in your image textures 3DM 20  Textures For optimization purposes, whenever possible, you should consider: Simulate large patterns by using tiled smaller textures Reuse the same texture in different areas of the scene (applying a different pattern/ transformation) 3DM 21  Textures Almost all + = environment with 2 textures (9,31Kb) 3DM 22  Textures For optimization purposes you should consider: Simulate surface attributes such as reflectivity and roughness with textures Efficient simulation of real textures in a 3D surface (use transparency) The creation of complex 3D content with minimal investment of polygons (sometimes a simple plane is enough) 3DM 23  Textures Use (and abuse): normal, bump, reflection, occlusion, specular and displacement maps 3DM 24  Textures + Illumination Use light maps to pre-compute the demanding lighting effects 3DM 25  Textures + Illumination Pre-computed lighting with unreal engine Source: http://bit.ly/2LHPQCN 3DM 26  Virtual Textures Is a procedure that reduce the GPU memory usage and texture loading time when using high resolution textures in a scene Concept: Split textures into tiles, and progressively upload these tiles to GPU memory once they are needed dfdsssfsdfss dfdsssfsdfss 3DM 27