Contents:
Background, Fog and Landscape - Access ---- Background, Fog and Landscapes - Overview ---- Backgrounds ---- Fog ---- Landscape Objects ---- Customizing and Tricks

Illustrated to the right, I show the Render pull-down menu which consists of all the same tools as those found on the Render toolbar.    In this Part we will be discussing three tools for adding simple environmental effects to your Renderings.  These effects include Background colors and images, Fog and Landscape "image-objects".

Backgrounds are one of the easiest ways to add graphic atmosphere to a Rendering and you can use Backgrounds to affect Materials that have a Reflective Attribute value.  Backgrounds will also help to lighten Renderings that appear dark.

Fog is the closet to an actual atmosphere control and can be used to create a the illusion of actual Fog or as a tool to fade back areas with little to no detail.

Landscape objects are the most complicated in this discussion but offer one of the most exciting and fast ways to drop clip-art objects into a Rendering to assist in adding "real-life" elements such as Cars, Trees and People to 3D architectural geometry.  In this discussion, you will also learn how to make your own Landscape objects to take even greater advantage of this simple trick to make Renderings look more realistic.

Menu	View> Render> Background...
Keyboard	BackGround
Links	Section 3 - for full story on Backgrounds

Using the Background dialogue box should prove to be one of the easiest things you can do to dramatically affect a Rendering.   Through this dialogue box, you can set the background to render as a simple monotone color, a custom gradient color, a custom bitmap image or a working screen merger.

In addition to controlling how the background looks in renderings, you can also add a reflection background with the Environment option so that reflective materials reflect exactly what you want; even if it's something completely different than what is in the current drawing.

Menu	View> Render> Fog...
Keyboard	Fog
Links	Section 4 - for full story on Fog

Using the Fog dialogue box may prove to be more complicated than the Background dialogue box but its function is rather simple: it allows you to add a volumetric gradation based upon a chosen color, intensity percentages and distance percentages.

the Fog dialogue box also provides the option to affect the Background which will allow you to turn a sunny sky gray.

Menu	View> Render> Landscape New...
Keyboard	LsNew
links	Section 5 - for full story on Landscape

Using the Landscape New  dialogue box should prove to be one of the most amusing tasks you can perform to affect a Rendering.   The only really bad thing about the this feature is the limited library that comes with AutoCAD and Architectural Desktop.  Fortunately, AutoCAD and Architectural Desktop come with a Landscape Library equipped with the ability to Add your own Landscape "image-objects".

Landscape "image-objects" are a composite of two images ( one for the image and one for the transparency around the image ) mapped to a 3D triangular face and are basically the Rendering equivalent of cut-n-paste images.

Menu	View> Render> Background...
Keyboard	Background

On the Background dialogue box, illustrated to the right, you can use the Solid radio button to set a monotone color as your Rendering Background.

Colors
Top - this is the only option available for the Solid Color option.   It will not be available if the AutoCAD Background checkbox is checked.

Color System - use this drop-down list to choose between RGB ( Red, Green and Blue ) or HLS ( Hue, Lightness and Saturation ).   Once you have selected either of these two Color System methods, you can adjust the current Color by a set of matching controls.  For Solid Colors it seems most logical to simply use the Select Custom Color button.

Select Custom Color  - use this button to access the Color dialogue box where you can choose a color from among the numerous True Colors.

AutoCAD Background - uncheck this checkbox to use the settings available check to have your Rendering use the current screen background color as the Rendering Background Color.  This is the default when starting new Renderings.

Environment - see discussion below.

Tip: Blue-Screening - if you plan to use Photoshop to add background scenery or other effects, use a uniquely contrasting color that will be easy to select with the Magic Wand or Color Filter.  To avoid having this color show up in reflections, use the Environment option to set another bitmap image for reflections.

Menu	View> Render> Background...
Keyboard	Background

On the Background dialogue box, illustrated to the right, you can use the Gradient radio button to set a three-part range of colors as your Rendering Background.

Colors
Top - this is the only option available for the Solid Color option.   It will not be available if the AutoCAD Background checkbox is checked.

Color System - use this drop-down list to choose between RGB ( Red, Green and Blue ) or HLS ( Hue, Lightness and Saturation ).   Once you have selected either of these two Color System methods, you can adjust the current Color by a set of matching controls.  For Solid Colors it seems most logical to simply use the Select Custom Color button.

Select Custom Color  - use this button to access the Color dialogue box where you can choose a color from among the numerous True Colors.

AutoCAD Background - uncheck this checkbox to use the settings available check to have your Rendering use the current screen background color as the Rendering Background Color.  This is the default when starting new Renderings.

Environment - see discussion below.

Menu	View> Render> Background...
Keyboard	Background

On the Background dialogue box, illustrated to the right, you can use the Image radio button to set a bitmap image as your Rendering Background.  You can use this technique to add a photo-realistic sky behind and above your buildings.

Image
Name - use this text field to specify the path, name and extension of the bitmap image that you want to use for your Rendering Background.  Use the Find File... button if you are not familiar with the information required in the Name text field.  There are two good sky images in the default texture folder that comes with AutoCAD and Architectural Desktop: "sky.tga" and "sunset.tga".   See Bitmap Texture Location if you can't find these images.

Adjust Bitmap - use this button to access the Adjust Background Bitmap Placement dialogue box, also illustrated to the right. 

Environment - see discussion below.  Illustrated to the right, I show that I have chosen to use the Use Background option because I want my reflective Materials to reflect the sky.tga bitmap so that the Rendering looks cohesive.

Adjust Background Bitmap Placement dialogue box
Fit To Screen - uncheck this checkbox to allow for stretching and scaling of the bitmap background image to better match the needs of your Rendering.  This is a good option of your background image has a Tile seam near one of the edges or your rendering.   With a little scaling, you can correct this type of problem but too much scaling will distort an image.

Use Image Aspect Ratio - uncheck this checkbox to allow for Scaling that literally stretches the bitmap background image. 

Tile and Crop - these two radio buttons are the same as those found on the Material Mapping dialogue box.  Using Crop is a good way to prevent a Tile effect but may leave a good portion of the background empty.

Offset - use these X and Y value boxes or their equivalent scroll bars to move a bitmap image around in the background.  This is a great option when attempting to position a sun, for example, with specific geometry in a Rendering.  The only way to get it right, is to use trial and error Renderings until the location meets your needs.

Scale - use these X and Y value boxes or their equivalent scroll bars to size a bitmap image relative to the Rendering Area ( see red frame ). 

Adjustment Caution:
If you plan to produce high resolution renderings and have modified the Background bitmap image, as illustrated above, be sure to re-adjust the bitmap image for the resolution of your final rendering or it will end up too small.  Therefore, you may be best off using the Fit To Screen checkbox to guarantee a full Background at any resolution.

Menu	View> Render> Background...
Keyboard	Background

On the Background dialogue box, you can use the Merge radio button to produce Renderings that actually display all linework ( not just 3D objects ) in the working screen.  This will only work, however, for Renderings produced on the screen using the Viewport Destination option on the Render dialogue box.

Environment - see discussion below.

Menu	View> Render> Background... ( Environment options )
Keyboard	Background ( Environment options )
Links	Bitmap Texture Location - for information on where to find the default bitmap image files.
	Reflective Attribute Value - for information on how to make a Material produce a Mirror-like reflection.

The Environment option that is available for all of the Background types, offers the ability to control a component of what Reflective Materials reflect.  These are Materials that use the Mirror Attribute option and not a bitmap image for their reflective Color.  By setting a bitmap image file and path in the Name text field ( use the Find File... button ), this image can be used exclusively for objects with Materials that have a Reflective Attribute Value.  By using this feature, you can add more "life" to some objects while keeping a simple Background.

Use Background - use this checkbox to deactivate the use of any bitmap image for the Environment.  If a Background image is currently used, and the Material on an object has a Reflective Attribute Value, it will reflect the Background as well as other Objects, Materials and Landscaping.  Uncheck this checkbox to use a bitmap image for the Environment.

No Environment - if you choose to have no Environment options set, objects with a Reflective Attribute Value will reflect AutoCAD's / Architectural Desktop's screen background color.  However, some materials that have a Reflective Attribute Value  use their own bitmap image and thus will reflect this image no matter what is set for the Environment ( this is the case with all of the Chrome Materials in the default Materials Library ).

Menu	View> Render> Fog...
Keyboard	Fog

On the Fog dialogue box, illustrated to the right, you can Enable Fog for the 3D Geometry and the Background image, set Fog Colors, control Fog placement and Fog falloff percentages.

Fog is basically a gradient across the distance between the Camera and the Target which can be used to create the illusion of an atmosphere.  This means that Fog does not have to be Gray but can be other colors as well.  Of course the gradient will always appear as a haze of some sort but it can be quite useful.  On projects where there should be a lot of background information, you can use the Far Distance and Far Fog Percentage to fade the horizon off to a shade of gray.

In the graph illustrated to the right, I have attempted to show how the four components of Fog work together.

In many cases, and I highly recommend starting at this point, simply using the Far Distance and Percentage values are ideal.  The Near values control a point from the Camera or view out to the Far Distance value ( which must be at least 0.01 for Near to work at all ).

Distance is a measurement taken from the camera or viewers position to the target or back clipping plane.  The camera's position is always set to zero while the horizon is at 1.00 or 100% of the distance.   This means that when you specify a distance percentage, you are referring to how far you want to be from the camera relative to the total distance between the camera and the horizon ( target ).  In other words, 0.10 is closer than 0.90.

Near Distance - use this value field to set the point at which you want the Near Fog Percentage to End.  You can, for example, have the Near Fog Percentage set to 0.20 ( 20% ) at a distance of 0.10 ( 10% ) from the camera.  This will start a gradient value between 0% and 20% from the lens of the Camera to a point 20% ( or 1/5 of the distance out to the target ).

Far Distance - use this value field to set the point at which you want the Far Fog Percentage to Start.  The Fog will start at this point and continue to the target where it will have a gradient value set by the Far Fog Percentage value. 

Near Fog Percentage - use this value to set how dense or dark you want the gradient to be at the distance set by the Near Distance.

Far Fog Percentage - use this value to set how dense or dark you want the gradient to be at the target ( the farthest point out on the horizon ).

Note:
Setting a Near Distance greater than the Far Distance can create puzzling results.   Doing this pushes the Far Fog Percentage back thus overriding the true function of the Far Distance value.  This does not mean that this is not a valid approach to creating an effect but that it can cause results that are difficult to figure out if you are not sure about what you are doing with Fog.

Menu	View> Render> Landscape New...
Keyboard	LsNew
Links	Landscape - Adding Trees - for another example

On the Landscape New dialogue box, illustrated to the right, you can select from among the eleven "image-objects" that come with AutoCAD and Architectural Desktop.  This sample library has a variety of objects that demonstrate how useful this form of adding clip-art can be to make Renderings a bit more realistic.

The process is based on that discussed in Part 7 - Materials ( see Bitmap as Transparency Attribute for a specific example ) where two bitmaps are combined to create the appearance of transparency around the actual image.  One bitmap holds the tree, person, car, sign, or other photographic image while the other bitmap uses a black and white mask to indicate where transparency occurs ( black portion) and where a solid image occurs ( white portion ).  The reason two images are required is that bitmaps can only be rectangular in form thus preventing such irregular shapes as those formed by organic objects.

When you Position a New Landscape object, the physical appearance in your Model will be a triangular face that is oriented by the UCS.  This face can be Copied, Scaled and Edited with the Landscape Edit dialogue box.

Menu	View> Render> Landscape Edit...
Keyboard	LsEdit

On the Landscape Edit dialogue box, illustrated to the right, you have a very limited number of options.  You can change the Geometry, View Alignment, Height and Position but you cannot change the Landscape type.  Height cannot be change beyond the Value of 100 Units so that offers a bit of a limited option as well; especially when you are working with trees like Palms and Redwoods.

To make a Landscape object taller or shorter, simply use the Scale command.

Landscape objects come with an insertion point that you can OSNAP to for better accuracy in Editing.  To acquire this insertion point, use the Center OSNAP.

Menu	View> Render> Landscape Library...
Keyboard	LsLib

On the Landscape Library dialogue box, illustrated to the right, you can access other Landscape Libraries, Create new Libraries, Modify, Delete and Create New Landscape objects.

To create a New... Landscape object to the current Landscape Library, you will need two bitmap images as illustrated to the right.   For the actually Image File you want in your Rendering, you will need to clear out all areas that you want to be transparent around this image.  For the Opacity Map File you will need an exact copy of the primary image file where all of the imagery is white.  This file will act as the mask where all of the black areas will be transparent.

Default Geometry
Single Face, Crossing Faces and View Aligned - see Landscape Edit dialogue box for explanation of these options.

Name - this will be the Landscape Library name

Image File - use the Find File... button to locate the actual bitmap image that you want seen in your Rendering.

Opacity Map File - use the Find File... button to locate the copy of the actual image where the image area is white and the transparent area is black.

Illustrated to the right are two .jpg images that can be used to create a New... Landscape Library object based upon the discussion above.

Right-Click over each image and use the Save As... option to save these two images to a project folder on your machine.

Once you have saved these images to your machine, use the Landscape Library dialogue box and create a New... Landscape object for the current Library based upon these two images.