The scaling of 3D models is realtive to the target. That is, the smaller the target, the smaller the augmented 3D model. The 3D model will be rendered with default size. Scaling the model allows you to control the size of the 3D model. When using the Wikitude 3D Encoder you can roughly estimate the size of the 3D model. If your 3D model fits into the square with the dimension 1 unit in the 3D Encoder as shown in the image below you can use 1 as value for 3D Model Scale. If your model uses 2 grid units, you need to set the value to 0.5 and so on.