Materials Mapping

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.

IMPORTANT! ElumTools does not utilize the generic reflectance data set for the Space in Revit MEP (ceiling, walls, floor). This data is for Revit’s estimating routine only.


The ElumTools Material Mapping dialog has two levels of functionality as set in the upper left corner and shown in the images below: View Project Materials and View Category Overrides. Initially, when you access your Revit project with ElumTools, all reflectances will be set by material and there will be no Category Overrides in effect. This state of material mapping is the most complex and requires that all of the materials in-use in the Revit project be verified for accurate reflectance values. While this step should never be ignored entirely, it is possible to “override” the materials used in “common” categories such as ceilings, walls, floors, glass and others, and replace them by category with a single material reflectance value. This is the function of the “Category Overrides” section of the dialog.


HINT! As a simple best practice, first select the View Category Overrides 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. All other material reflectances will be set by material (Furniture for example).


Setting Reflectance by Material

  1. Select the radio button for "View Project Materials". On the left side of the dialog, you will see Revit material names with the Graphics Color and Graphics Transparency properties extracted from the Revit project by ElumTools. The corresponding mapped ElumTools properties for each material are shown on the right. A green arrow is shown initially in the "Link" column to indicate that ElumTools is utilizing what can be obtained from the Revit material. Select a material by clicking anywhere along the line.
  2. Material reflectance is automatically computed from the RGB component of the Revit Graphics Color (see "Reflectance" below). If the Graphics Color is not appropriate, select a different color and/or reflectance from the ElumTools materials side.
  3. The default Surface Type is "Opaque" for Revit materials. Revit material names including the words "Glass" or "Glazing" are automatically assigned a Transparent surface type with the following exceptions: "fiber glass", "glass fiber" and "fiberglass". (See Transparency below).
  4. 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.

  5. If you would prefer that a material be completely removed from the ElumTools calculations, set the surface type to Ignore. If the material name contains the word "ignore", the surface type is automatically set to Ignore.
  6. When using linked models, the materials must be mapped in both the host model and the linked model. You may find it easiest to make the mapping changes in the host model, then save the material map. Change the material mapping dialog to display the linked model from the pull down menu (see image below) and then load the same material map to apply the properties.
  7. When you have made the desired changes to the materials map, the project is ready for calculations from a materials perspective.




The default condition for the dialog is to sort all the Revit materials and show those currently "in use" at the top. The "In Use" property can be adjusted in two ways; by toggling the "in Use" materials from top to bottom of the list using the In Use button, or by placing a check mark in the In Use box to show only materials that are in use in the list.

Setting Reflectance by Category Override

  1. Select the radio button to "View Category Overrides" in the upper left corner of the dialog. ElumTools changes the dialog to display a list of Revit Categories. Using this feature it is possible to "override" the material reflectance settings for all materials within a certain "category". For example: all items in the Furniture category could use the same reflectance regardless of material.
  2. Place a check mark in the box at the left side of the category name and then set the reflectance for that category.
  3. ElumTools lists several "Common" categories at the top of the list by default. They are: Ceilings, Floors, Roofs, Walls, Interior Glass and Daylight Transition Glass (used for daylighting only). Here you can easily set a common reflectance and transmittance for these categories which will override all material settings. This is a very easy way to simplify the work of setting reflectances and transmittances in your Revit projects.
  4. Category overrides apply to the main model and all linked models.




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.


Surface Reflectance

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

Transparency and Transmittance

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

Saving and Loading Material Maps

ElumTools Materials Manager provides the capability to save the settings from the dialog as a map for later use with another project if desired. It is then possible to load the map and have all identically named materials automatically setup for your current work in ElumTools. Simply use the Save and Load buttons in the lower left corner of the Materials Mapping dialog.


Advanced Material Properties


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