IDEAS: "Drops" are special non-movable objects that are part of the scenery. They cannot be moved, and they don't make the prop-pointer appear when you point at them. Characters can hide behind drops. The drops in a scene are listed in a file with the same name as the scene, and the extension ".drp".

Drops have a third dimension, because they are "in front" of the stage. So we have to study how the Z coordinate works together with X and Y.

OUTCOMES: At the end of this lesson, you will have added some large boulders so that your dino can hide behind them, to surprise the other dinos.

NEEDS: Dino5.wld. Copy it from your WORLDMAS folder if necessary.

Step 1: Three Dimensions.

When we want to measure things in the real world of three dimensions, we normally use a traditional (X, Y, Z) system where X goes to the right, Y goes up and Z comes out at the viewer. See the left-hand picture on the next page.

Most computer systems, including ExploreNet, use a different system. X is still across the screen, but Y is measured down from the top of the screen. Z still comes out at the viewer. See the right-hand picture on the next page.

In the ExploreNet worlds you've seen so far, the world has looked two dimensional. The characters and props are flat, like paper dolls. But if you think about it and experiment, you will discover that one character or prop is always in front of, or behind, another one. (We call characters and props "objects"). The rules for deciding what's in front are simple.

RULE 1: The "X, Y, Z" of an object is measured at the center of its base. For instance, consider this clueless looking fellow.

RULE 2: The Z coordinate of any moving object is automatically set equal to its Y coordinate. This rule means that the farther down the screen an object's foot is located, the closer it is to the viewer.

RULE 3: Objects with larger Z coordinates appear in front of objects with smaller Z coordinates. This rule means that things closer to the viewer seem to block things farther from the viewer. The world would be very confusing if this weren't true!

You can test these ideas by starting up ExploreNet and selecting Dino5.wld. There is a boulder in the Prairie scene.
                                   

Step 2: Drawing your own Scenery

We need a rock big enough for your dino to hide behind. The demonstration boulder in the Prairie scene was only large enough for a Raptor. If you're using Paint Shop Pro (PSP), do this:

Go to the FILE menu of PSP and select OPEN.
Go into EXPLORE.NET/UNIVERSE/DINO5/SCENES and open Prairie.bmp.

Now use OPEN again; go to the directory named EXPLORE.NET/UNIVERSE/ DINO5/OBJECTS and open one of the poses of your personal dinosaur. It will appear in front of the Prairie scene, in its own window.

We want to have the scene and dino where we can see them, so as to draw a boulder that fits into the scene and which is big enough for your dino to hide.

Go to the FILE menu of Paint Shop Pro and select NEW.
Set your new drawing's size to 150 x 150.

If this isn't big enough to make a boulder than can cover your dino, use IMAGE:RESIZE and make it bigger. The first number is the picture's width, the second is its height. These are measured in "pixels" (picture elements) which, unfortunately, are not the same measurements the ExploreNet screen uses.

Now you can see a little window in front of the big one. We'll draw our boulder in the little window.

Use the COLORS menu; LOAD PALETTE. Go to EXPLORE.NET\WORLDMAS and load up the 'XNET.PAL' palette.

In the SELECT menu bar, double click on the foreground color square (it's the one on the top.) This opens up the palette.

Select the background black color (upper left corner); close the palette window with OK, and use the paint can to pour a solid black background for your boulder-making.

Use the marker pen painting tool to make a nice big boulder. It should be bigger on the bottom than the top, so that it doesn't look like it'll fall over. Make it big enough to cover your dinosaur. Make some marks on the boulder with a few different rock-ish colors, so it isn't just one big blob of one color.

Now save the object in the EXPLORE.NET\UNIVERSE\DINO5\OBJECTS directory, with the name Rock1.prp. (Because we already have a Boulder1.prp, you're going to have to name yours, Rock. Did you know you're now a Rock Star? Some of us are Boulder than others..... )

Make sure you select FILE SUB-FORMAT as WINDOWS RGB ENCODED. Otherwise ExploreNet cannot read the file!

Step 3: Connect the Rock into your World.

Each scene in a world that has drops, must have a "drop file". This is a list of the drops in that scene. Of course, Dino5.wld already has a file named Prairie.drp, stored in the SCENES folder.

Use the File Manager to locate the file named EXPLORE.NET\UNIVERSE\DINO5\SCENES\PRAIRIE.DRP. Try double clicking on it.

If double-click doesn't open up the NotePad or WordPad editor, then you need to Associate the extension 'drp' with your favorite editor as we did in earlier lessons.

In this file we find the original boulder listed:

boulder 300 500 500 : Its X, Y, Z location

Unlike a Prop file (.prp), there is no number to describe how many poses - because a drop always has only one pose. Also, the Z coordinate of a drop is required, whereas Z is optional (and actually rather useless) for props.

Add a new line, like this

rock 600 500 500

although you can use your own choice of X and Y. Use the Arrow object to find a nice X, Y location.

SAVE the file. Now - DON'T exit from NotePad; we'll need it later. Just use CTRL-ESC to switch back to the File Manager for the next step.

Step 4: Test the Rock.

Start up ExploreNet, if you remember how. (Find its icon and click on it! Or, use File Manager and look in EXPLORE.NET\CODE and double click on EXPLORE.EXE.)

From the green screen, click NO NETWORK.

This will automatically load up whatever's in UNIVERSE, which is your Dino World.

When the world loads up, take your personal dinosaur, go to the Prairie scene and try to go behind the rock. As long as your feet are higher than the bottom of the rock, you should be hidden.

But what if you wanted to "float" the rock further out in front, so that you could do a trick like what we see in the following scene?

Step 5: Making Multiple Drops

By now you may have thought of having an orange grove, or a field full of Christmas trees, or a parking lot full of cars (anachronism: a detail that is not consistent with the story's time. As in, a car in Dino World.)

See if you can figure out how to do this, too, by working logically from the example for multiple eggs back in Lesson 4.

FEEDBACK FORM FOR ExploreNet LESSON 5

Coral Springs Middle School - Spring 1996

Student Name:_____________________ Date:____________

1. Please list any problems you had with our lesson worksheets? Did we ask you to do anything that didn't work out as planned? (What page number? What action?)

2. Did the ExploreNet software work correctly? If not, tell us as exactly as possible what you were doing when things went wrong.

3. What did you like best about this lesson?

4. What did you like least about this lesson?

5. What should we add to this lesson to make it better?

ANSWERS: To make an object come farther forward, just increase its Z coordinate. Your rock could be at 300 500 800 for instance, instead of 300 500 500.

To make multiple Drops in a scene, just name them as follows:

Rock1 (Rock) 300 600 700 : or wherever you want it to be
Rock2(Rock) 400 700 800 :etc, etc.