Texture	A texture is a file which can be loaded and mapped onto a 3d surface. You could load an image called bricks.gif and map it onto a sphere. This, of course, is done from within your rendering application.
Bump Map	Typically, a bump map is a gray scale image of the texture that your rendering application uses to simulate roughness of a surface. A bump map allows you to simulate fine details without actually modeling them. Ripple Rain uses animated bump maps to simulate water impact ripples.
Alpha channeled textures	The alpha channel in a TGA file refers to transparency information that your rendering software can use when painting textures onto 3d object. The higher the value in the alpha channel, the more opaque that pixel will appear.
Window	A window, as defined in this document is a workspace within a screen.
Screen	--fill in--

When you create a project and render it to disk, you’ll end up with a wide variety of file names and formats each with their own specific purpose. Water impact ripples are saved in the common windows bitmap format (*.BMP). To animate ripples, you simply paint the texture onto a horizontal plane in your 3d rendering package as a bump map.

Rain is saved as alpha channeled TGA files (ie, 32 bit TARGA) that are painted on planes that are perpendicular to the object that the ripples bump map was painted on. By placing these "rain planes" parallel to each other, each with different rain drops in different locations, it will give the illusion of falling rain to your animation without the need for a particle system. As well, rain planes allow you to maintain an extremely low polygon count.!

Toolbar	Project loading and saving, layout functions, rendering functions and tools are accessible from here.
Layout Window	The layout window is where emitters are laid out that generate water impact ripples. If you are creating rain, the location of an emitter also serves as the target for the rain drop. This window is your workspace which is a top view of the horizontal plane show above.
Emitter Detail Window	Emitters which exist in the layout window will also appear in the emitter detail window. This window is a detailed view of a give emitter in a treeview that works similar to Windows Explorer.

File Operations	Create a new project, load an existing project, and save current project.
Layout	Emitter mode, precision add emitter, snap to plane, show fade radius, show termination radius, variances, and rain parameters.
Rendering	Preview water ripples, render rain and water ripples.
Tools	Create action/plane alignment guides, and rain wizard.

	When clicked, you’ll be prompted for the x and y resolution of the layout window. The layout window resolution will be used by Ripple Rain when creating impact ripples and rain textures.
	an existing project.
	When pressed, left clicking in the layout window will bring up the add emitter dialog box. After parameters are set, an emitter will be added to the project at the cursor location.
	Since Ripple Rain will create a series of alpha channeled rain maps for each emitter that is on a unique y axis, using snap to plane will give you more control over emitter placement. When pressed, any emitters that are added will snap to the nearest plane.
	When pressed, the radius at which point the ripple begins to fade is shown as a dark grey circle.
	When pressed, the radius at which point the peak height of the ripple becomes zero is displayed as a light grey circle.
	When the emitter mode icon is pressed in conjunction with the variance icon, any emitters added by right clicking in the layout window will have their parameters increased or decreased by the percentage entered.
	When clicked, a dialog box will appear requesting various parameters for animating rain.
	Rough preview of water ripples movement. Clicking the eye con will give you an idea of how fast ripples will expand and how far they move. Not a true 30 fps preview.
	Render textures. When clicked, a dialog box will appear that allows you to set up various rendering options such as filenames and locations.
	Refresh layout window.
	Create plane alignment guides and emitter action guides. Clicking this icon will give you textures that can be used for aligning the rain planes with ripple planes from within your 3d rendering application.
	Rain wizard is a fast and easy way to create water ripples and rain. In five steps, you can create an entire ripple rain project and render it.

You can add emitters to your project by pressing the emitter mode icon and then clicking in the layout window. Whenever you click inside of the layout window, an emitter parameter screen will appear. This screen is divided into two sections: Emitter Profile and Ring Profile.

Ring Profile	Information which tells Ripple Rain how to create your bump map. You simply draw the silhouette you want to create on your bump map.
Emitter Profile	Defines ripple expansion, movement and decay will affect the silhouette drawn.

Simply put, the ring profile defines how a single ripple looks and the emitter profile defines how the ring acts.

You can load profiles by clicking on a filename from the list on the right. To save or delete a profile, simply click the disk or x icon.

From the diagram above you can see that the longer the silhouette (from left to right), the more broad your ripple will appear. As well, the higher the silhouette, the greater the amplitude of the bump map. You can further adjust amplitude from within your 3d rendering package.

To draw your own silhouette, simply click inside the ring silhouette and a screen will appear which is a zoom view of the silhouette for easy editing.

Just draw the silhouette by holding down the mouse button and drawing your silhouette in the grid. Remember to start at the left edge. Remember that as soon as your silhouette has no height, Ripple Rain terminates the silhouette. Be sure to start at the left edge and work your way over. When you click ok, you’ll see the new silhouette on the emitter parameter screen you just came from.

Let’s take a closer look at the emitter profile parameters:

Emitter Name	Naming your emitter greatly reduces the complexity of projects with a large number of emitters.
Number of Rings	An emitter emits rings (or water ripples) in the shape of the silhouette drawn at the top of this dialog. Enter the number of rings you want the emitter to create here.
Number of Frames Between Rings	The number of frames that passes between emissions of rings. Smaller numbers create rings more quickly.
Number of Pixels Radius Grows per Frame	This parameter determines how fast rings move away from the emitter.
Emitter Becomes Active on Frame	An emitter is dormant until its active frame is the current frame. When this happens, the emitter will begin emitting rings. Tip: After you define an emitter and are back at the main screen, you can right click in the layout window to quickly add a new emitter with the same parameters. You’ll be prompted for an active frame number for the new emitter.
Successive Ring Decay Value	When a water ripple is created, the first ring is very pronounced and obvious. Each ring thereafter has a height which is a little bit smaller than the last as the liquid in which the ripple appears is absorbed. The value in this parameter is how much each ring will decay. For example, if you had a ring silhouette which had a height of four and the successive ring decay was set to one, the second ring would have a height of three. The third a height of two and so on. Tip: Be careful not to enter a decay value which overtakes your silhouette before all rings have been emitted. A good rule of thumb is to set your decay to a value greater than silhouette height divided by the number of rings being emitted.
Radius to Begin Fading	When an emitter becomes active, it begins to emit rings. These rings constantly expand at the rate entered in the "number of pixels grow per frame" parameter. After a while, you’ll want your rings to slowly fade into oblivion. Since Ripple Rain doesn’t know how you plan to use the bump maps created (scale and so forth), you can specify the radius at which a ring begins to fade here.
Number of Units to Fade Pixel Each Frame	Once a ring reaches the value entered in radius to begin fading, the value entered here will gradually decay the bump map’s amplitude to make the ring slowly fade into the surface.

The emitter that’s currently selected will appear in red in the emitter layout window. You can delete the emitter by right clicking when the emitter name is highlighted and selecting delete. As well, you can change any parameters shown above by double clicking on the parameter.

It makes sense to strategically place your emitters on the same y axis as existing emitters. This maximizes the number of rain drops on each rain plane. The snap to plane feature can assist you in placing your emitters on planes where other emitters exist to minimize render time.

It should be noted that the number of rain planes used is directly proportional to the realism of the effect achieved. More rain planes create a more believable simulation of rain fall but also take longer to render and take up more disk space.

Snap to plane is a mode that can be turned off and on. If you plan to use snap to plane, it’s best to turn it on at the beginning of your project so you don’t have to manually edit emitter locations to force them to exist on a specific y axis.

Note: Any emitters you add before engaging snap to plane will not be moved to a plane when you turn it on.

When you click the icon, a dialog box will prompt you for the number of rain planes to create. After you select a number, you’ll see the specified number of planes represented by horizontal gray lines in the emitter layout window. These are your rain planes. Clicking the snap to plane icon again will turn snap to plane off.

While snap to plane is on, you can add emitters (with the emitter mode button pressed) to your project simply by clicking near any of the gray lines. The new emitter will automatically be placed on the nearest rain plane.

The screenshot below shows emitters snapped to six planes.

Speed add works great with variances.

When you click the rain parameters icon, you’ll see a dialog box like the one shown below:

Let’s take a closer look at the rain parameters:

Color	Specify the color of rain by clicking the color. Normally, you’ll want a light gray or white color but we’re not going to restrict you to any one group of colors.
Width	Enter a value from 1 to 5 for the width of your rain drop. If you’re creating an animation which is smaller than a full screen render, it’s possible that rain drops wont appear in the final animation because of the fine detail. Using a wider rain drop will ensure that your rain is visible even in 320x240 animations.
Drop Length	The length of the rain drop. Observe a hard and fast rain and you’ll notice that you don’t see tiny dots of water. You actually are seeing a motion blur of where the water was terminating at where the drop is.
Trail Length	This is an optional parameter that allows you to create a motion blur for your rain completely independent of your 3d rendering package. This parameter is available because some rendering packages may not apply a motion blur to animated textures on stationary objects.
Number of pixels rain travels per frame	The value entered determines how fast your rain moves from the top of a rain plane to the bottom of the rain plane. Typically, you’ll enter a value equal to the resolution height divided by ten or twenty.
Rain Transparency Value	Real rain isn’t a solid color (unless it’s raining paint). It has some transparency to it. You can enter a value from 0 to 255 here. 0 is completely transparent and 255 is completely opaque. Click the preview window to update the view to the current parameters.
Static Trail Transparency	When this option is selected, you can enter a value in the trail transparency parameter.
Gradient Transparency	Selecting this option will create a trail which can best be described as an alpha gradient. It works by taking the rain transparency value and slowly increasing its transparency value in small increments until the final pixel is completely transparent. The increments used are determined by the trail length parameter.
Trail Transparency	If you are using a static trail transparency, you can enter a value from 0 to 255 here. 0 is completely transparent and 255 is completely opaque.

Choose a destination drive and directory for the textures you wish to create. All textures created will be put into the directory you chose on this screen.

If you want, you can render only ripples, only rain or both. Enter a filename for the ripples bump maps to be created and do the same for rain; if you want to create rain. Avoid using numeric values in filenames because they may confuse your rendering software.

Ripple Rain will number each texture created on according to its frame. For example, if you enter a ripples filename of "testripples", the resulting textures will be called "testripples001.bmp" for frame 1, "testripples002.bmp" for frame2, and so on.

Rain, however, is a little bit different. When you enter a rain filename, a texture will be created which includes the plane and the frame number. The format used is: (rain filename entered)(rain plane #)-(frame #). So, if you had two rain planes animated for four frames you’d end up with:

Under render options, you can choose to render all frames or enter a number of frames to render. If you enter 30, Ripple Rain will create textures for frames 1 through 30.

The three options create ripple action guide, create rain plane alignment guide, and create sample rain planes guide are explained below.

To begin the rendering process, click the render button and Ripple Rain will start creating your textures.

When you click the tools icon, you’ll see a screen like the one shown below:

You can customize the colors of the textures created by clicking any of the default colors shown. The base color is the background color of your texture while the line color is the color of text and impact points.

Here's some more information on the three different styles of alignment guides you can create:

Ripple Action Guide	This option will create one texture (named actionguide.bmp) that is useful in keyframing action in your scene to water ripples in your Ripple Rain project. Think of it as the bridge between Ripple Rain and your rendering software. This texture shows every emitter in your project with a number next to it showing the frame on which it becomes active. For example, you could use the action guide to keyframe movements of a stone as it skips across a pond. And when you're ready to animate, remove the texture and paint the animated ripple bump map on to the plane.
Rain Plane Alignment Guide	Selecting this option will create one texture (named planealignment.bmp) which can be used to line up rain planes with your animated impact ripple bump map. To use it, paint this texture onto a horizontal plane in your rendering package. Create vertical planes of the same sizes and place the planes between the lines shown on the texture. And when you're ready to animate, remove the texture and paint the animated ripple bump map on to the plane.
Sample Rain Planes	This option will create one texture (named rainalignxxx.bmp) for every rain plane. These textures show the rain plane number and where a rain drop will fall based upon the emitter location in the emitter layout window. Rain planes are meant to be used in conjunction with rain plane alignment guides. After you align your planes as described above, you can paint these sample textures on to those planes to see where rain will fall. When you're ready to animate, just repaint your rain planes with the corresponding animated rain plane texture.