If your content needs to be compatible with glTF 2.0 standard for some reason (such as for posting your model on Facebook), you can use physical materials for this purpose as described below.
Add a Physical Material shader node as follows: go to Materials/Map Browser and choose Physical Material from the General material list.
Then you can connect texture nodes to the Physical Material as described below. Note that all textures are optional and any of them can be safely omitted.
Connect an Ambient Occlusion texture to the Base Weight Map input. For better consistency between the 3ds Max viewport and Verge3D you can also connect the Ambient Occlusion texture to the Refl Color Map input, but it's not necessary.
Connect a Base Color texture to the Base Color Map input.
Connect a Roughness texture to the Roughness Map input.
Connect a Metallic texture to the Metalness Map input.
Connect a Normal texture to a Normal Map node and then connect it to the Bump Map input of the Physical Material. You should also set the Bump Map Amount value in the Special Map panel of the Physical Material to 1.0.
Connect an Emission texture to the Emission Color Map. You should also set the emission factor to 1.0 in the Basic Parameters panel of the Physical Material preferences.
The Transparency map will be taken from Alpha Channel of the Base Color texture.
Color Space and Gamma Correction
For correct rendering, the color space should be taken into account for images. All images, except the Base Color and Emission textures, must be presented in the linear color space. To do this, select Override Gamma with the 1.0 value in the Gamma Preferences when you open an image in the Open Image dialog box (as can be seen below).
On the contrary, the Base Color and Emission textures must be opened in sRGB color space (with Gamma 2.2). To make it happen, just leave Automatic in the gamma preferences of the Open Image dialog box.
The engine will use the Alpha channel from the Base Color texture as a transparency map automatically, if it is present. To make the transparency visible in the 3ds Max viewport, connect the Alpha channel of the Base Color texture to the Transparency Color Map input.
Also in the Preferences of the texture, in the Bitmap Parameters panel you should set Mono Chanel Output to Alpha and RGB Channel Output to Alpha as Gray.
Exporting Textures from Substance Painter
To facilitate exporting textures from Substance Painter and to ensure maximum capabilities within the Verge3D engine we recommend using Verge3D export preset.
Place this preset file to the export-presets folder usually located in the My Documents\Allegorithmic\Substance Painter\shelf\ folder (create if not).
When exporting textures from Substance Painter, choose Verge3d for 3ds Max in the export dialog window so that all generated textures are compatible with the glTF 2.0 standard Verge3D is based on.