Streamlined Rendering in ACA
Rendering is the process of creating a raster image based on the 3D objects in a scene. A renderer is used to calculate the appearance of the materials attached to the objects in a scene and how lighting and shadows are calculated based on the lights placed in a scene. Environmental and exposure settings of the renderer can be adjusted to control the final rendered image. While the final goal of rendering is to create an artistic or photorealistic presentation-quality image, you might need to create many renderings before you reach that goal. The basic rendering workflow is to attach materials to the 3D objects of a model, place user-defined lights, add a background, and start the renderer with the RENDER command.
A rendered image can be created for a new model without attaching materials, placing user-defined lights, and adding a background. By default, a default material is added to all 3D objects in a model and the renderer automatically uses two default distant lights when user-defined lights are not placed in a scene. As an alternative to the two default distant lights, you can specify the use of a single default distant light that shines from over-the-shoulder. Default lights cannot be moved or adjusted.
Materials represent substances such as steel, concrete, cotton, and glass. They can be applied to a 3D model to give the objects a realistic appearance. Materials are useful for illustrating plans, sections, elevations, and renderings in the design process.
Materials also provide a way to manage the display properties of object styles—using materials makes displaying objects more realistic. You need to define the display of a material, such as brick or glass, only once in the drawing or the drawing template and then assign it to the component of an object where you want the material to display.
You typically assign materials to components in the style of an object, such as the brick in a wall style. Then whenever you add a wall of that style to your drawing, the brick of that wall displays consistently. Defining materials in an object style can provide control for the display of objects across the whole project. When the characteristics of a material change, you change them just once in the material definition and all objects that use that material are updated. With the material tool you can apply a material to a single instance of the object.
You can take advantage of Visual Styles, Rendering Materials, Lights, and Cameras in AutoCAD® Architecture. Materials provide the ability to assign surface hatches to objects. Surface hatches can be displayed in model, elevation, and section views. This is helpful to clearly illustrate sections and elevations. Let’s take a closer look at materials.
You can use the Materials Browser to navigate and manage your materials within an AutoCAD Architecture drawing. You can organize, sort, select, and search materials for use in your drawing. The Materials Browser is where you can access the Autodesk library as well as user-defined libraries. To access the Browser, select the Render tab of the ribbon, Materials panel, and then Materials Browser. The browser contains the following main components (see Figure 1):
- Search – This allows you to search for materials within multiple libraries.
- Document Materials panel – This displays a set of display options for the materials saved in the current drawing.
- Material Library panel – This lists the categories in the materials libraries that are currently available. The materials in the selected category are displayed on the right. The buttons for applying or editing the material become available when you hover the mouse over the material swatch.
- Browser bottom bar – This contains the Manage menu, which provides options for adding, removing, and editing libraries and library categories. It also contains a button for controlling the display options for the library details.
Figure 1: Materials Browser
The Autodesk library contains more than 700 materials and over 1,000 textures. The library is read-only, but you can copy Autodesk materials into the drawing, edit and save them to your own library. There are three types of libraries:
- Autodesk Library – This contains predefined materials provided by Autodesk for use by all applications that support materials. It contains material-related resources such as textures and thumbnails. Although you cannot edit the Autodesk library, you can use these materials as a basis for customized materials that you can save in the user library.
- User Library – Contains materials that you can share with other drawings. You can copy, move, rename, or delete user libraries. You can access and open existing user libraries created locally or on a network and add them to your defined libraries in the Materials Browser. The libraries are stored in a single document and can be shared with other users. However, any custom texture files used by the materials in a user library must be manually bundled with the user library.
- Document Materials – Contains materials that are used or defined in a drawing and available only to the current drawing.
The materials in the Materials Library are typically assigned to 3D objects. AutoCAD Architecture objects that you can assign materials to are: curtain walls, walls, doors, windows, railings, roof, stairs, spaces, slabs, railings, mass elements, mass groups, and structural members.
To manage a Materials Library in AutoCAD Architecture, click the Render tab of the ribbon, Materials panel, and then Materials Browser. At the bottom of the Materials Browser, click the Manage Library drop-down list. You can now do the following:
- Open Existing Library – This displays the Add Library dialog box where you can select any existing library.
- Create New Library – This displays the Create Library dialog box where you can save the new library.
- Remove Library – Select the library and then click Remove Library.
- Create Category – Select the library and then click Create Category.
- Delete Category – Select the category and then click Delete Category.
- Rename – Select the library or category and then specify the new name.
You can add materials to a library by opening the Materials Editor, right-click the material, and select Add To. Now select the library where you want the material added. You can add the material to multiple libraries if desired.
It is important to note that materials you use more often can be placed on a custom tool palette for easier access. Click the Tool Palettes window title bar and click New Palette (see Figure 2) to create and name a new palette. The palette is customizable and you can add material tools by copying and pasting from other material palettes. The controls for doing so are on the Tool Palettes window shortcut menu.
Figure 2: New Tool palette
A material can be applied to individual objects and faces or to objects on a layer. You can apply materials to objects in three different ways:
Assign material definitions to individual components of an object through the display properties of its style.
Use a material tool to apply a material definition directly to an object component in the drawing.
Apply a render material from an AEC material definition to an AutoCAD object.
The Design tool palette includes the default Material tool, which references the Material Definitions file and allows you to apply any of those material definitions. Many of these material definitions can also be applied through material-specific tools located on the Materials tool palette in the Visualization palette group. You can also create custom material tools from other existing tools, from material definitions in Style Manager, or from render materials in the Content Browser.
To apply a material to an object or a face, first select the object and then select the material from the Materials Browser. The material is added to the drawing and it is also displayed as a swatch in the Materials Browser. When creating or modifying a material in the Materials Browser, you can click a material in the library and the material is applied to any selected objects in your drawing. Drag the material swatch directly onto objects in your drawing or assign a material to an object by clicking the Assign to Selection in the shortcut menu on the material swatch in the Materials Browser.
You can assign a material to a layer by entering MATERIALATTACH at the command prompt. The Material Attachment Options dialog box will open and you can drag a material onto a layer (see Figure 3). When applying materials to objects by layer, the material is applied to all objects on the layer whose Material property is set to BYLAYER.
Figure 3: Material Attachment options
A material is defined by a number of properties. The available properties depend on the selected material type. To begin, open the Materials Browser. Next on the browser toolbar, select Create Material. Now, select a material template (see Figure 4). This opens the Materials Editor. Enter a name for the material and specify the material color options. Finally, use the sliders to set the properties for shininess, opacity, refraction, and translucency. You can also copy and modify an existing material. It is important to note that the material GLOBAL is always available in a new drawing. This material is applied to all objects by default until another material is applied.
Figure 4: Creating new materials
After a material is created and applied, the properties can be modified in the Materials Editor. The material swatches that are available in the drawing are displayed in the Materials In This Document section of the Materials Browser. When a material swatch is double-clicked, the properties for the material become active in the Material Editor sections (see Figure 5).
As you modify the settings, they are saved with the material. The changes are displayed in the material swatch preview. By holding down the button below the swatch preview window, a set of fly-out buttons display different geometry options for the material preview.
To modify the name of a material, open the Materials Browser and select the material. Right-click and select rename. Now you can change the name and description of the material in place.
If you wish to change the material preview shape and render quality, this can be done by opening the Materials Editor and then select Options. Now you can select a different swatch shape and render quality for the material.
Figure 5: Materials Editor
Manage and Organize Materials
Managing and organizing materials is important to ensure less confusion in finding what you are looking for. When a material is moved, a copy is created and it is added to the new category. If the material is copied into the root node, its original category is maintained and it is recreated in the new library. There are two ways in which to move materials:
- Drag and drop – You can drag swatches or materials from a library to the Materials in This Document section in the Materials Browser. You can also drag materials from a library to another library. A new copy of the material is created and saved with the drawing.
- Shortcut menu – You can use the shortcut menu to copy a material to a new library. Use the Add To option and then select material in the library copied to the document or a library material copied to another library.
You can search the materials in all open libraries based on the material’s name, description, and keyword information entered in the Materials Editor. All the materials are filtered to show only those matching the search string. Only the materials that have a match for the search string are displayed. Click the X button in the search box to clear the search and return to viewing the unfiltered library.
The search results depend on the library you have selected in the tree view. For example, if you select the Library root node, it displays the search results for all matching materials in the selected library. However, if you select a category it searches only within that category.
You can delete a selected and unlocked material by using the shortcut menu or with the Delete key. It is important to note that locked materials cannot be deleted from the Materials Browser or from the shortcut menu.
When a legacy material (any material created in AutoCAD 2010 or earlier releases) is shown in the Materials Editor, you have the option to convert the material into an editable format. After the conversion, the Materials Editor controls are enabled and editable.
Legacy materials are rendered, but not editable in the application. It is recommended to convert these materials to their Generic equivalent. The new materials provide better results and can be shared across Autodesk applications.