Creating a 3D Object #2 Before starting this tutorial itself, it is vital to explain the principles and basic ideas which govern the use of the 3D system offered by Canvas. Firstly, it is important to recognize that the objects are made up of individual lines, which, when separate, have no solid form, but when placed in a formation create a 3 dimensional image. Solid objects cannot be created. The only way of creating these is to plot an object (wire frame) and draw in the edges (using the user-defined polygon mode for instance) - also see tutorial #3. The object editor is known as the 3D Construction Studio and is capable of storing 8 objects at once, each containing up to 256 separate lines. This number of lines should be easily adequate for any object you want. Each of these lines consists of 2 points (the Start and End, of course). The editor is based on a 1st angle orthographic projection. Sounds gruesome eh? It simply means that you edit the lines on 3 planes (x,y and z) using an Above, End and Side view. Creating a 3D Cube We'll take a cuboid shape to use in this example. Consider the shape of a cube - it has 12 edges so we will need 12 lines eventually. It also consists of 6 faces. Since the 3D editor is not POLYGON-BASED, we must ignore the sides themselves and just think of the cube as a formation of 12 lines. 1) Fortunately, the editor offers the possibility of setting up a formation of lines which form a polygon. Set the Poly Sides Infobar to 4 (each side has 4 lines). Now press the Add Poly button and select a square(ish) shape - it will appear more like a diamond, but never mind! 2) Select Y as the Axis and use the Shift> to shift the diamond on the Y Axis again, but the other way, so that it is opposite the centre from where it was before. 5) Again click the Add Obj button without changing the Infobar value. You should now have two diamonds at different heights and a total of 8 lines in existance. 6) Keep increasing the number in the Line Infobar until you find a line which does not exist (a cross at the bottom right of the screen means that it doesn't exist and a tick means that it does). The value should be 8. 7) Click on the Add Line button to bring Line 8 into existance. A dot will appear in the centre of the edit windows. Note that both ends of the line are at 0,0,0 0,0,0. Click on the edit windows to move the ends of the lines. To change which end of the line you edit, use the S/E (Start/End) Selector in the bottom left. You will find it very difficult to position the ends of the lines in the right places. To help you, you must switch on the Fix button. Now, if you click on the Edit windows, the point will be placed at the nearest point already in existance to the place where you clicked (think about it!). So, if you click near one of the corners of a diamond, that point will be placed at that corner - no messing around trying to be mega-accurate! 8) Create another 3 lines and place them vertically between the 4 corresponding vertical pairs of point on the 2 diamonds. 9) Now check that there are 12 lines in existance (see value in bottom right), and that the object in the edit windows looks about right - it may be a little hard to visualize, but there should not be any diagonal lines except for 4 on the Above view. If there are, something has been done wrong. Go through the lines using the Line Infobar until the suspect line appears in a different colour to the rest - lo-res only. Change the line's position so that it is correct. 10) Now that you have the cube, click on the View Obj button to enter the Viewing Studio. You will see in the centre of the viewing window the cube. Rotate and move it about until you are happy about it and then press Plot to place it onto the current work screen. Phew!! That was quite a 'tuffie' to explain! If you can't visualize an object on the edit windows then load in the "EXAMPLE.3D" file (in the "_THREE_D" folder) and look through the objects in that.