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The function of the ElumTools Material Mapping section is to set the reflectance of the various materials in the Revit model to ensure your lighting calculations are accurate. Surface reflectance information, especially relative to the major surfaces of ceiling, walls and floors, is critical for lighting calculations making material mapping a required step prior to calculation of lighting results
IMPORTANT! ElumTools does not utilize the generic reflectance data set for Spaces in Revit MEP (ceiling, walls, floor). This data is for Revit’s estimating routine only.
There are three dialog states for ElumTools Material Mapping:
By Material - Initially, when you access your Revit project with ElumTools, all reflectances will be set by individual material as described further in this topic. This state of material mapping is the most detailed and requires that all of the materials in-use in the Revit project be verified for accurate reflectance values.
By Category - It is possible to “override” the materials used in common Revit categories such as ceilings, walls, floors, glass (and others), and replace them by category with a single material reflectance value. There are no Category Overrides in effect initially.
Show Selected (only) - This is an optional check box which can be applied to show only materials or categories associated with the currently selected elements (selected in Revit). This is convenient as you can select an element (or several) in Revit such as Spaces, Rooms or Regions prior to selecting the Material Mapping command in ElumTools. The Material Mapping dialog will then open showing only the materials and category overrides that are in-use within the element boundaries you have selected.
HINT! As a simple best practice, first select the ByCategory button. At the top of the list, in the Common Categories, place a check in the boxes for Ceilings, Walls and Floors. Set the reflectance to be used for each of those categories.
When the dialog is in the "By Material" state it tabulates all of the materials in all Projects (linked models). The materials currently in-use are check marked. The Project column lists the specific project (or model) where each material resides.
If you would like an altered ElumTools property setting to be forced back into the Revit materials list, set the link arrow to Bi-directional. Otherwise, any changes to the ElumTools properties will result in a red bar in the link column showing that the changes are not pushed back into the Revit materials list; they are simply used for ElumTools lighting computations. Note: materials in linked models cannot have bi-directional links.
The default condition for the dialog is to show materials currently "in use" with a check mark. Place a check mark in the In Use box to show only materials that are in use in the list.
The "By Category" state of the dialog shows Common Categories at the top of the dialog. You can assign a reflectance value to the Category and effectively override the material settings for all materials used on entities in that category. Using the by Category option makes it extremely easy to set reflectances for Ceiling, Walls and Floors for all calculations.
Enabled (checked) category overrides can be easily filtered to the top of the dialog by checking the "Category Override box at the top of the check box column.
HINT! It is possible to remove an entire category from any calculations in this section of the dialog. Simply enable the category override and set the Surface Type to "Ignore".
HINT! You can easily set multiple categories to the same reflectance value by using the SHIFT and/or CTRL-select techniques on the rows of categories, then enabling the override (checkbox) and setting a single reflectance value within the selection.
Known Limitation: "Show Selected (only)" in Material Mapping does not detect elements which have been selected in Linked Models using "Tab Select".
ElumTools Materials Manager provides the capability to Export the materials settings from selected Projects as a map for later use with another Revit project if desired. Simply check mark the desired projects to Export and click OK. A Windows Explorer dialog will appear allowing you to name and save your exported material settings.
You can Import previously exported materials settings using the Import button. This will allow you to override materials in any current Project (model) with saved materials settings. This can save you the effort of defining materials in the new project. If new materials are contained in the map to import you can elect to bring them in or disregard.
ElumTools calculates the surface reflectance from the Red, Green, and Blue (RGB) components of the material "Graphics Color" in the Revit materials section. The relationship between grayscale reflectance (overall reflectance) of a surface and its RGB color equivalent is as follows:
Grayscale Reflectance = 0.2125 * R + 0.7154 * G + 0.0721 * B
where R,G and B are expressed as numbers between 0 and 1.0 (when RGB is expressed by numbers between 0 and 255, divide by 255).
More on Color & Reflectance
Most surfaces in Revit and ElumTools will be Opaque with reflectance calculated as described above. However, ElumTools also supports Transparent and Translucent surface types.
Revit surfaces utilizing the words "glass" or "glazing" in the material name will be automatically translated in the Materials Mapping section to a "Transparent" surface type in ElumTools using the rules described above. ElumTools does not automatically apply a "Translucent" surface to any Revit material. Translucent surfaces in ElumTools are constructed by setting a "Transmittance" in the Color, Reflectance and Transmittance dialog.
ElumTools utilizes an image-preserving capability with transparent surfaces such that direct light will pass through correctly and be reduced by the selected setting for transparency. Translucent surfaces are considered as Lambertian (diffuse) transmitters. Please reference the following topic.
Transparent vs Translucent
Advanced Material Properties
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