What is LOD?<\/h2>\n\n\n\n
LOD or the level of detail <\/strong>is the method of reducing the number of polygons in 3D objects based on their distance to the viewer or camera. Modelers use it to reduce the workload on the CPU or the graphics card and increase the efficiency of rendering. <\/p>\n\n\n\n Correspondingly, there are various levels of detail groups<\/strong> created for each piece of the game scenery. Each of them has a different polygon count and belongs to a group, where the LOD0 group is a fully detailed model and LOD1, LOD2 \u4e00 have a lower level of detail, and so on. <\/p>\n\n\n\n It can range from several thousand triangles in a polygon mesh<\/a> on the most detailed object and barely a hundred on the least detailed version of the model. <\/p>\n\n\n\n If you\u2019re wondering whether it influences players’ experience \u4e00 the answer is yes and no<\/strong>. <\/p>\n\n\n\n The reduced visual quality of the model is rarely paid attention to since objects are distant or moving fast. However, rendering time is significantly improved which doesn\u2019t go unnoticed.<\/p>\n\n\n\n While it seems like a one-size-fits-all solution, you still can\u2019t apply it to all games. <\/p>\n\n\n\n Note: <\/strong>don\u2019t use LOD on very simple objects with a lot of triangles or games with static camera view. In these cases, mesh optimization is handled differently.<\/p>\n\n\n\n Different objects are located at different distances to the viewer during the game. So, distance solely is not a valid factor for defining the level of detail for each object, character and scenery. <\/p>\n\n\n\n There other some other metrics to consider too:<\/p>\n\n\n\n Once you define these, you need to choose which technique to use to create LOD for your object.<\/p>\n\n\n\n LOD helps to <\/strong>deliver adequate visual quality while avoiding unnecessary computation <\/strong>with the help of the algorithm. However, modern approaches are tailored to the rendered information which is far from what the original algorithm was prone to do. <\/p>\n\n\n\n Based on the situation there are 2 main methods.<\/p>\n\n\n\n Utilizing the discrete method, you create multiple discrete or distinct versions<\/strong> of the object with a different level of detail. To obtain all of them you need an external algorithm used in various polygon reduction techniques.<\/p>\n\n\n\n During rendering, those versions of the objects with a higher level of detail are substituted for the objects with a lower level of detail and vice versa. It causes a visual popping during the transition which you should at all times.<\/p>\n\n\n\n A continuous level of detail method is best suited for performance-intensive applications and moving objects.<\/strong> It allows you to vary the detail locally. As a result, you can present one side of the object closer to the viewer with more detail and the other side with a reduced level of detail. <\/p>\n\n\n\n It is possible because of the structure used in the method where the spectrum of detail continuously varies. CLOD enables you to choose the level of detail appropriate for certain situations. Because of the few involved operations, this method provides both lower CPU and faster performance<\/strong>.<\/p>\n\n\n\n When you start creating polygon meshes, the first question that pops up in your head is \u30fc what is the reasonable number of LOD?<\/em><\/p>\n\n\n\n It may sound simple, but it is the second important thing to know after you learn what is LOD. <\/p>\n\n\n\n And here is why.<\/p>\n\n\n\n If you reduce just a few vertices in a polygon mesh there won\u2019t be any significant performance improvement. All versions of the object will be rendered almost the same. Then, if you reduce the polygons too much, the LOD switching will be too noticeable. <\/p>\n\n\n\n Pro tip:<\/strong> use an unwritten rule of reducing the number of polygons by 50% for each object of the group (LOD1, LOD2, LOD3, etc), but still tailor it to the size and importance of an object.<\/p>\n\n\n\n![\"how](\"https:\/\/3dstudio.co\/wp-content\/uploads\/2022\/02\/how-to-edit-level-of-detail.jpg\")
![\"different](\"https:\/\/3dstudio.co\/wp-content\/uploads\/2022\/02\/different-level-of-detail.jpg\")
LOD Parameters<\/h2>\n\n\n\n
![\"lod](\"https:\/\/3dstudio.co\/wp-content\/uploads\/2022\/02\/lod-parameters-level-of-detail.jpg\")
<\/figure>\n\n\n\nLevel of Detail Management Techniques<\/h2>\n\n\n\n
Discrete Levels of Detail (DLOD)<\/h3>\n\n\n\n
![\"discrete](\"https:\/\/3dstudio.co\/wp-content\/uploads\/2022\/02\/discrete-levels-of-detail-dlod-lod-groups.jpg\")
<\/figure>\n\n\n\nContinuous Levels of Detail (CLOD)<\/h3>\n\n\n\n
![\"continuous](\"https:\/\/3dstudio.co\/wp-content\/uploads\/2022\/02\/continuous-level-of-detail-lod.gif\")
<\/figure><\/div>\n\n\n\n![\"continuous](\"https:\/\/3dstudio.co\/wp-content\/uploads\/2022\/02\/continuous-lod.jpg\")
Optimize the Level of LOD for a 3D Object<\/h2>\n\n\n\n
![\"how](\"https:\/\/3dstudio.co\/wp-content\/uploads\/2022\/02\/how-to-create-lod-groups.jpg\")
<\/figure>\n\n\n\n
Besides, LOD meshes cost you memory and CPU workload. So, too many of them will require much processing and increase the file size. Keep that in mind.<\/p>\n\n\n\nHow to Create LOD Meshes?<\/h2>\n\n\n\n