In this tutorial, you will be learning how to create an LOD system (render based) within few easy steps. For those who don’t know about LOD system, LOD stands for Level of Detail. In an LOD system, we create basically three versions of a geometry (high, mid and low poly).
The work of LOD system is to switch the geometry detail levels according to the distance between the geometry and the view / camera. More the distance between the view / camera and the geometry, less will be the detail, similarly, less the distance between the view / camera and the geometry, more will be the detail. So, let’s learn how to create one.
Step1
Here, I have head model of a female character with three versions (high, mid and low poly) available. I named them according to their detail level as High, Mid and Low.
Step2
Let’s align them at the top of each other with the help of Align tool (Alt + A).
Click here to learn more about Align tool
Step 3
Now, go to Utility panel and click on Level of Detail Button. If you don’t have Level of Detail utility there, then you can find it under the Utility list simply by clicking on More… button.
Step 4
Before creating any LOD set, we have to group our all the three head geometries so, select all the three models then go to Group > Group. Under Group dialog box, feed the Group name as LOD set or whatever you want.
Step 5
Now, select the group and click on Create New Set button (Level of Detail rollout). This will add all the three geometries to the utility to create an LOD system. We can also choose a detail level to be displayed on the viewport. Currently, Low level is active for the viewport but you can activate any level that you want – simply by double clicking that level or by turning on Display in Viewport option for that level. I am using Mid level for my viewport.
What are Max Size Min size threshold values in Level of Detail Utility?
Min Size
It is the minimum size of the object after which it gets switched to the less detailed geometry.
Max Size
It is the maximum size of the object after which it gets switched to the more detailed geometry.
Let’s take an example of an LOD set which has three LOD levels High poly, Mid poly, Low poly with following Min and Max sizes:
Low poly:
Min Size: 0
Max Size: 25
Mid poly:
Min Size: 25
Max Size: 50
High poly:
Min Size: 50
Max Size: 100
Let’s assume that LOD level High poly is currently active. Now, what happens when we zoom out the viewport:
Active LOD level: Highly detailed Geometry (Min Size: 50 and Max size: 100 >> Viewport zoom out >> Geometry exceed the Min Size threshold >> Switched to the geometry with less detail level (see image).
Maximum Size works the same way for an LOD level with less detailed geometry. The less detailed geometry get switched to the more detailed geometry / LOD level when it exceeds the Maximum Size threshold.
Step 6
We can see the detailed version (High) of the head geometry in the render, when we are closer to it. It changes to the low res geometry when we go away from it. I just adjusted the thresholds of the LOD set to make it easy to recognize the LOD level in the render.
I hope you enjoyed this tutorial. Let me know your queries and suggestions through comments section or just throw me an email. Good luck.
