A prospective customer is fond of pasting decals onto glass panels as opposed to sandblasting them, although they may want to sandblast in any case. Creating decals in Revit is an easy matter, as images, bump patterns and cutouts are readily accommodated. For a detailed description on how to create a cutout refer to http://www.mgfx.co.za/non-rectangulait-decal-image/. To illustrate where the Revit to Lumion workflow breaks down, the different scenarios are illustrated below. Firstly, a simple decal without a bump pattern or cutout is created in Revit and then brought into Lumion.
A similar decal is now created albeit with a bump pattern applied. Note that Lumion no longer knows how to interpret the decal.
As a workaround, a standard material can be created instead, using a “normal map” to represent the bump pattern. A normal map uses RGB colors to represent vector directions, hence a simple bump pattern can be created using blue.
https://forum.lumion3d.com/f-a-q/lumion-6-quickstart-guide/msg405541/#msg405541
https://en.wikipedia.org/wiki/Normal_mapping
Here is the normal map (blue represents Z)
Select a decal from Revit that has not rendered. Apply a standard material.
For the Color Map, the image is selected, and for the Normal Map, the Blue bump pattern is selected. Automatically the second instance of the decal is similarly rendered.
Cut out decals from Revit are not recognized by Lumion either, and one does not have the ability to create a cut out in Lumion.
If the cutout has a simple geometry then an extrusion can be modeled in Revit. Applying a material to this in Lumion is not a trivial process, and the controls are finicky. After a few iterations this is the closest I could get.
Applying a material to the extrusion in Revit is more rewarding, but again non-trivial.
Shown above are the results for an equal amount of effort expended in Lumion and Revit. My recommendation would be to be pedantic about creating the cutout and then to adjust the image and alignment within a Revit Material. This then renders automatically in Lumion. Unfortunately it is found that bump maps applied to the extrusion material does not port to Lumion.
In contrast a Lumion material can have a normal map applied to it.
In conclusion, if a geometrically simple decal cut out using a texture needs to be applied to a glass material, model it as a single instance, thin face based component in Revit and then create a standard material in Lumion and adjust the scale and offset until the required result is achieved.
