SketchUp - Extensions

The plugin supports several Maxwell extensions, which generate render elements at render time:

Extension	Description

Extension	Description
Maxwell Grass	Accessed via the Maxwell Grass window, this extension produces grass blades on geometry.
Maxwell Sea	Accessed via the Maxwell Sea window, this extension produces a sea surface, using Next Limit RealFlow technology.
Maxwell Volumetric	Accessed via the Maxwell Volumetric window, this extension produces a region containing participating media.
Maxwell Scatter	Accessed via the Maxwell Scatter window, this extension scatters instances of an MXS file over a surface.

All of these extensions are created by assigning data to a SketchUp group. Their respective windows track the active selection, with changes made being applied to all currently-selected groups. At the top of the windows you will find an item named Selection, which indicates how many groups are selected, as well as the most recently selected group:

Three groups selected - Last one called Plane

In this example, there are three groups selected, with the most recently selected one being named "Plane". The grass blades will be applied to all the objects in the group (if this was the Scatter extension, all the MXS instances would be distributed over the objects in the group). Oftentimes, groups have not yet been named, in which case, this selection would appear as:

Setting up the maps in the extensions panels (density, length, rotation, etc.)

SketchUp is a bit limited in terms of texture controls, so we have to jump through some hoops to set their scale as we want. Imagine you want to set a density map to distribute some cones (or flowers, or trees) over a plane that also has a texture for the ground using the Scatter extension.

1st case; the size of the soil texture is the same as our density map.

The easiest workflow is to generate an additional material that uses the density map we want for the cones. If we apply this material temporarily to the base plane, we can check in the viewport that the location of the scattered objects is the one we want, then apply the ground plane material back to the base object. As the texture sizes are the same, we don't need to do anything else. In this case, I have distributed some red cones over a plane and used a circle of dots as a density map:

2nd case; you want to have a different texture size for the density map and the main material texture.

The procedure would be the same as in the first case, but after assigning the ground material back to the base objects, you should use the Maxwell texture controls from the Scene Manager > Material tab to change the texture size as, if you use the SketchUp controls, the density map would also be modified. Here I used a crosshatch pattern for the ground geometry while keeping the previous density map (note I changed the crosshatch pattern size in the Scene Manager window and its size in render no longer matches what is seen in the viewport):

About the base point of the instances in the Scatter extension.

Maxwell will pick the coordinate 0,0,0 as the base point for the instance, so, when you generate the MXS file in Studio or from the plugin (Right-click > Maxwell > Export selection to > MXS), just make sure the objects are in the right place relative to the center of the scene (it will be their base point). The Scatter extension will place the origin of the MXS file on the surface of the grouped geometry and locate the included objects relative to that point.

Details about the different extensions

For information on the meaning of the parameters contained in each window, please see the relevant documentation:

All of these use geometry in their group, and/or its bounding box, along with the transformation of the group, to define how they are created and rendered in Maxwell.

Be aware that it may be very easy to create extensions which use a great deal of memory, and which may therefore crash the SketchUp process.

Here is a simple example of Volumetrics creation: