Once you have pressed or clicked on [View], you are presented with a screen that looks like the one on the right. Normally, when the mouse is over the grid area, it looks like this and when it is over other areas it looks like this . There are a number of things that you can do with the 3D Optimisation graphs depending upon what you want.
	You can click the mouse on any uncalculated point to calculate it - during the calculation, the cursor looks like this . To find out where the optimum result lies for the two variables that you have chosen, you can either fill in the entire grid or search for the maximum. You can do these by hand or you can get the program to do them for you using Fill and Search respectively.
	Pressing or clicking on Fill will fill up the entire grid with calculated points. This may take some time depending upon the speed of the computer running the program, the number of points and the time slice that you have selected for the calculations. The Fill function picks grid points at random so that if you have selected meaningless grid limits, you will be able to see that there is going to be a lack of any useful points early on, instead of having to wait for the entire grid to print. You can terminate the Fill operation by pressing any key. When the screen is full, it should look something like the screen shot on the right. As the points are calculated, the program works out the range and puts the values for each colour on the right, effectively creating a z axis. As you move the mouse around the grid, you will see the mouse's x and y axis values appearing in the bottom right and top left respectively. You will also see the z axis value appearing in the top right. If the values for a particular point have caused an error, the appropriate error message appears instead of the value. See and below for another Fill function.
	Pressing or clicking on Search will locate the maximum on the grid much faster. In addition, the speed is not proportional to the product of the number of points on the axes but proportional to their sum thus making this method faster still. On selecting Search, the z axis range is squashed to the top (see below) so that the top of the range uses most of the colours, the mouse cursor changes to this and you start the search by clicking somewhere on the grid. The search function works by selecting a random direction and a random rotation (clockwise or anticlockwise) and then calculates the point where the mouse was clicked. It then travels in the chosen direction, calculating as it goes, until it comes across a result that is less than the highest that it has found so far. It then changes direction, according to the rotation that it chose at the beginning, and calculates that, repeating the search process until it finds an isolated maximum. It then produces the eight pointed star pattern in the screen shot on the right just in case there is a lot of granularity in the graph - it being fairly probable that any new maximum will be picked up by this process. You can terminate the Search operation by pressing . This method works fairly well with roundish shapes but can produce unreliable results with very thin diagonal maxima that do not fall at 45 degrees on the grid. To get around this, simply run the search function a few times or manually calculate the points you suspect to be maxima.
	Pressing or clicking on Zoom will change the cursor to and you can then select the lower left corner of the area that you want to zoom in on. The program will highlight the grid point that you click on and you can then click on the upper right grid point. Once you have done this, the new points will be inserted into the upper and lower limits on the form and the new graph grid will be plotted. You can terminate the Zoom operation by pressing .
	Pressing or clicking on Adopt changes the cursor to and you can now select a point on the grid. The x and y values of this point will be inserted into the Input Parameters form and then copied onto the input ranges form of the 3D Optimisations ranges thus providing new ranges. The Adopt procedure speeds up considerably the process of inserting optimised values into the input parameters sheet and if you have three parameters to optimise, you can Search, Adopt, select new parameter pair, Search, Adopt . . . and so on until you have the best starting values for your real rocket. See Calculations for some examples of this in action. You can terminate the Adopt operation by pressing .
	Pressing will change the background from black to white or back again. It also updates the checkbox in the Graph part of the 3D Optimisations page. Changing the background will not change the colour scheme that you have selected although it will redraw the screen. If you have done something that has made the system draw on the screen, such as swapping to another program and back on some versions of Windows 95, you can use to redraw if you want.
	Pressing the number keys will change the type of graph selected in the order that they appear on the Results part of the optimisations page. They are as follows:
	Maximum Height;     Maximum Speed;     Maximum Acceleration;     Time to Apogee;     Flight Time; and,     Distance Downrange.
	In this way, you can look at the different graphs with their different outputs without having to recalculate them each time.
	Pressing or clicking on the vertical lined box (on the left) will split the screen into vertical lines, each with their own maximum and minimum. This is what has been done with the screen shot on the right. The three boxes on the left show the current status of the screen - on the right, it is divided into vertical slices. If you have the screen sliced like this and press or Fill, the cursor changes to to signify that you can choose which vertical slice to fill. Fill works as it does normally with any key cancelling the process. This type of plot is used to find the best height, flight time and so on of one variable against another. In the example on the right, you can see the best amount of water for any particular rocket weight. Note that this is for the specific pressure, nozzle diameter, coefficient of drag and so on that was used to obtain the graph. This type of graph (say for another example, launch angle for a given rocket weight giving maximum downrange distance) can be useful for taking into the field where you may not be able to use a computer.
	Pressing or clicking on the horizontally lined box will divide up the plot into horizontal slices. Again, if you have the screen sliced like this and press or Fill, the cursor changes to to signify that you can choose which horizontal slice to fill. Fill works as it does normally with any key cancelling the process.
	Pressing or clicking on the box with the square in it will return the plot to its normal state.
	Clicking on the colour scale on the right, or dragging the mouse up or down it will squash up the top or bottom of the scale by varying degrees. This is done automatically when you go into Search mode but you can do this for yourself, selecting the best looking scale distribution for your purposes.	Dark colours at the top for a white background.
	Pressing will change the colour set that the plot uses. There are a number of scales, from monochrome, through mono-tint to various coloured scales with some more suited to a black background and some to a white background. Pressing repeatedly will simply cycle through them.
	Pressing or clicking on OK will exit from the 3D plot.
	Errors are produced when the model comes across a situation that is not compatible with expected flight. If there is not enough water to get the rocket to the end of the launch tube, for instance, this will produce an error which manifests itself on the plot as a bubble and when the cursor is over that point, as an error message instead of a value. The error messages are as follows . . . Error Message Usual Cause   Low Pressure = Not enough pressure to push out all of the water.     Low Water = All of the water has been expelled before the rocket has got to the end of the launch tube.     Light Rocket = Weight of rocket too low - needs to be a realistic weight as too low a weight will generate too high an acceleration.     Low Capacity = Not enough room for all of the water you are trying to put in there.     Small Nozzle = The nozzle diameter is below a lower limit.     Hole Position = Holes in side of Launch Tube are too far from the end to be inside the rocket at the start of launch.     Small Chute = Chute diameter must be bigger than that of the rocket.     Vol/Press Err = Volume of liquid too great.     Low Thrust = Not enough thrust to keep the rocket off the ground until the end of the water thrust phase.     Low Gas Dnsty = Density of gas is below an arbitrary limit.     Low Temp = Temperature set below absolute zero.     Short Impulse = Air impulse less than 1ms.     Short L/T = Launch tube less than 1cm long.     L/T Dimensions = Launch tube less than 1mm in diameter.     Large T-Nozzle = T-nozzle diameter less than 0.01mm or greater than nozzle diameter.     L/T Thickness = Launch Tube thinckness is greater than the launch tube radius.     Invalid Angle = Angle of launch less than 5º.     Chute in thrst = Chute opened during water thrust phase.     Error = Anything else not specified above.

Copyright ©2000 Paul Grosse. All Rights Reserved