Since Poliigon no longer supports the specular workflow, Lumion users may find that they'll want to update to at least Lumion 2023, which supports a full PBR workflow.
Lumion Support
Textures: Full PBR Texture Support (Available from Lumion 2023)
Models: .FBX Support
HDRIs: Full Support
How to import Poliigon Models into Lumion
To import models into Lumion, make sure you’re first selecting .fbx as your download format from Poliigon. Then follow these steps:
While in Content Library in Build Mode, click on the Imported Models button and then click on Place.
This will bring up your Imported Model Library. Simply click on this button to import your model:
The model will then snap to your mouse in the viewport, allowing you to place it in your scene, either once, or repeatedly as many times as you left click. Hit ‘esc’ to exit placement mode. You can also switch placement modes from single to line, allowing you to place an array of models in a straight line.
You can view Lumion’s full guide here: https://support.lumion.com/hc/en-us/articles/12193299343260-Importing-and-Working-with-3D-Models
How to import Poliigon PBR Textures into Lumion
Here's a great video from Architecture Inspirations on how to import Poliigon materials into Lumon.
To import Poliigon textures using Lumion you can follow these steps:
To import materials into Lumion, select the model whose material you want to edit, by clicking on the material tab, then clicking on the object.
To use a material preset from Lumion’s built in library, just click through categories on the ‘Materials’ tab. To import a custom material, select the ‘New’ tab, and then at the top of the window, switch to the ‘Settings’ tab to access the individual inputs.
You can then add individual texture maps by clicking on the blank square to the right of the input name, which will display the ‘load map’ text if you hover your mouse over it.
Please note that Lumion expects a normal map in the Direct x format, but Poliigon provides OpenGL normals. To fix this, click the 3 dots at the right edge of the window for the ‘Relief’ (Normal) input, and select “Flip Green Channel”
Lumion also support displacement maps, however please note that it’s not true geometry displacement, but rather parallax displacement.
Additional inputs such as opactiy and subsurface settings can be found in the ‘Properties’ tab at the bottom of the ‘Materials’ window.
You can view Lumion’s comprehensive guide on materials here: https://support.lumion.com/hc/en-us/articles/7764034284188-What-do-the-properties-of-the-Standard-Material-mean-in-Lumion-2023-and-newer
How to import Poliigon HDRIs into Blender
How to import Poliigon HDRIs into Lumion using Real Skies
The easiest way to use Poliigon HDRIs in Lumion is to enable Real Skies. Lumion ships with a selection of Poliigon HDRIs available out of the box. Click on the ‘Weather’ tab of the bottom Navigation bar, then toggle the ‘Real Skies’ option:
How to import Poliigon HDRIs as a custom HDRI
If you wish to use a custom HDRI, you’ll first need to switch to “Photo” mode, on the left hand navigation bar. You can then load your image using the folder icon:
Lumion recommends using exterior HDR images with the horizon in the middle of the image for the best results.
You can view Lumion’s full guide here: https://support.lumion.com/hc/en-us/articles/360003474993-How-do-you-replace-the-sky-with-a-photo