Below there are two images I included in a recent blog post. Do you know those photo hunt games they have in bars? Well then, can you spot the difference?
The medium view in one of them has materials applied to it while the other one doesn’t. There is no existing Revit standard that indicates which approach to follow, but that shouldn’t deter us from trying to develop one.
So what would be our starting point for deciding whether materials should display in a project at a given level of detail? All things being equal, I would propose that it makes sense to display materials whenever a family’s geometry is meant to “depict” the geometry of the actual object. In coarse view, for example, most families have their geometry reduced to a volumetric representation or linework (which doesn’t even carry materials in Revit), so it doesn’t make sense to apply materials at that level of detail. Having materials visible at a coarse level detracts from being able to quickly interpret the visual information presented. On the other hand, there won’t be any more accurate depiction of an object in a project than at the fine level, so at that level of detail we should definitely apply materials to any families that have them. But what about at the medium level of detail? This one seems more open to debate.
In general, materials should be assigned to a material type parameter in the family, and the geometry’s built-in material parameter should be linked to the former. When working in large projects with many families, it’s not uncommon that geometry for the fine level gets “re-used” for the medium level of detail. If some or all of the geometry is shared between the fine and medium levels of detail, we can’t just turn off that geometry’s material for the medium level without doing the same for the fine level. So if we want to hide materials, we have to create completely new geometry for the medium level and leave that geometry’s material parameter set to “<By Category>”. But replicating geometry always increases file size, which we want to avoid whenever possible.
On the other hand, if we make materials visible at the medium level, then we can re-use as much geometry from the fine level as we want without any increase in file size, and in theory with little or no impact on the overall performance of the family within a project. Doing so might imply a few extra clicks per family to assign materials for geometry that only exists at the medium level, but the overall result will be a more accurate depiction of the project. Given that a family’s medium level of detail usually attempts to approximate its real world geometry, it seems best to settle with materials displaying at both fine and medium levels of detail, while not displaying at coarse levels of detail.
Again, I’m proposing this as a general rule of thumb and as a starting point for a more thorough standard for how to use materials in Revit families. I can certainly imagine there are cases where turning off materials at the medium level might make sense, but on the whole I believe making them visible offers greater benefit for projects with minimal to zero downside.
Are we on the right track here? Have you come across this issue when working with materials, or do you have a different standard that you follow for your projects? I invite you to share your thoughts or questions in a comment.
