OS/2 Professional

home *** CD-ROM | disk | FTP | other *** search

/ OS/2 Professional / OS2PRO194.ISO / os2 / wps / progs / view3d / manual.doc < prev next >

Wrap

Text File | 1993-06-07 | 14.1 KB | 265 lines

============================================================================= ============== 3-D W O R L D F O R O S / 2 2.x ============= ============================================================================= Copyright (C) 1993 by Shuqian Ying Written By Shuqian Ying ========================= M A N U A L ============================== Section 1. Model Definition: There are two ways of defining 3-D images in the present version of the program. 1.1 Defining the 3-D images through parametric analytic functions An example is z = f(x,y), f(x,y) = x^2 + y^2, which is one of the simplest cases. The program however allows you to generate the 3-D data set in a parameter space, such as x = f(u,v), y = g(u,v), z = h(u,v), provided that the regions defining the images in the (u,v) parameter space are rectangular ones of the following form u_min < u <= u_max, v_min < v <= v_max. 1.2 Defining the 3-D images through ASCII script files The format of these script files in the current version of the program is ---------------------------------------------------------------------- id: # | A non-negative integer id number. (0<= id < 30) ---------------------------------------------------------------------- Name: name | A string that labels a particular data set. ---------------------------------------------------------------------- Color: | A string that declares the color of the covering | surface of the image. The available colors are: | Blue, DarkBlue, Green, DarkGreen, Red, DarkRed, | Yellow, Cyan, Pink, DarkPink, White, Black, | Brown, DarkGray, PaleGray ---------------------------------------------------------------------- nu nv | nu is the number of mesh points on the u-axis | and nv is the number of mesh points on the v-axis. ---------------------------------------------------------------------- x1 y1 z1 | This set is the 3-D data block. The order of these x2 y2 z2 | 3-D data points are arranged such that the u .... | parameter is kept fixed while v run from v_1 to .... | v_nv, then u changes to its next value and v run xn yn zn | from v_1 to v_nv again. ---------------------------------------------------------------------- Coordinate | A string that signifies the beginning of the body | coordinate definition. ---------------------------------------------------------------------- xx0 xy0 xz0 | Two points that define the x_axis. It can be set xx1 xy1 xz1 | to {0 0 0} and {a 0 0} at the beginning, with "a" | a number of the same order as the size of the 3-D | object. ---------------------------------------------------------------------- yx0 yy0 yz0 | Two points that define the y_axis. It can be set yx1 yy1 yz1 | to {0 0 0} and {0 a 0} at the beginning. "a" | should be the same as the one for the x_axis. ---------------------------------------------------------------------- zx0 zy0 zz0 | Two points that define the z_axis. It can be set zx1 zy1 zz1 | to {0 0 0} and {0 0 a} at the beginning. "a" | should be the same as the one for the x_axis. ---------------------------------------------------------------------- next/end | A string signifies the termination of the data | set definition. If the string is "next", it also | signifies the begin of a next one. Otherwise, it | signifies the end of the definition. ---------------------------------------------------------------------- ..... | Repeat the above steps, if a "next" is read, to ..... | define another 3-D object to be plotted on the ..... | same screen. ---------------------------------------------------------------------- 1.3 Miscellaneous Information 1.3.1 Use different id for different part of the data set. Also nu >= 3 and nv >= 3 should be used for the current version of the program. 1.3.2 This demonstration program will not allow you to input another data set from a script file before cleaning up (see later part of this document) the current ones. 1.3.3 In addition, only a few predefined analytical (parametric) 3-D models are provided for demonstration purposes. If you like to investigate your own data set, use the script file method by generating the data file first. 1.3.4 Finally, error checking for file parsing has not been implemented. So script file with incorrect format will likely crash the program. Section 2. Actions 2.1 The viewer's motion: The motion of the viewer can be simulated by the mouse. 2.1.1 Adjusting open viewing angle The viewer can adjust his/her open viewing angle to simulate the effects of a telescope. This mode can be activated in the "Zoom" sub-menu of the "View" menu. After activating this mode, the viewer can zoom-in by clicking the mouse button 1 and zoom-out by clicking mouse button 2. To deactivate the zooming mode, click the mouse button 3 or the ESC key in case the viewer has a two button mouse or prefers to do so. In the current version of the program, the increment and decrement of the view angle for each click of the mouse button can not be changed by the viewer. 2.1.2 Walking The viewer can walk forward and backward in his/her focus direc- tion of viewing. This mode can be activated in the "Action" menu by clicking on the "Walk Stopped" item. Once the walking mode is activated, the "Walk Stopped" item is changed to "Walking..." indicating that the viewer is in walking mode. The viewer walk forward if he/she clicks the mouse button 1 and walk backward if he/she clicks the mouse button 2. This mode is deactivated by clicking the mouse button 3 or pressing the ESC key in case the viewer has a two button mouse or prefers to do so. In the current version of the program, the increment or decrement of the viewer's distance to origin of the world coordinate following each clicking of the mouse button can not be changed by the viewer. 2.1.3 Shifting focus The viewer can shift his/her focus (of viewing). The focus point of the viewer on the screen is assumed to be at the center. To shift the focus point, activate the shift focus mode in the "Action" menu. By pointing the mouse pointer to the point of interest and clicking the mouse button 1, the effects of shifting focus point in the real lift can be achieved. This mode is automatically deactivated when the program finishes the shifting focus process. 2.1.4 Simulations of viewer's motion The viewer can "fly" through and around the 3-D object in real time. This is a mini virtual reality (VR) mode in which the viewer can look around at all directions and move to anywhere in the virtual 3-D space. This mode is activated in the "Action" menu. After activation of this mode, the viewer moves to the right by moving the mouse to the right and he/she moves to the left by moving the mouse to the left. To move upward, the viewer should move the mouse forward (this is just opposite to the conventional airplane). Opposite direction of motion is achieved by moving the mouse backward. The speed of the forward flying is controlled by the frequency of the mouse button 1 been clicked. The speed of the backward flying speed is controlled by the frequency of the mouse button 2 been clicked. This mode is deactivated by pressing the mouse button 3 or the ESC key in case the viewer has a two button mouse or prefers to do so. 2.2 The manipulation of individual object The viewer can rotate, displace, scale or delete individual or a group of 3-D object(s) when it (they) is (are) active. To perform such transformations, the viewer should first activate the object(s) by turning on the "Select Models" mode, which can be activated in the "3D Models" menu, and clicking on object(s) that is (are) not active and is (are) of interest. (If the object is already active before been clicked, it turns the object into inactive mode after been clicked.) By selecting the "Transform" item in "Action" menu, providing the required parameters and turning on the transformation buttons, the viewer can achieve the intended transformation(s). The order or the transformations applied is the same as the one appears on the dialog box. 2.3 Relocation of the viewer The viewer can change his/her position of viewing from one location to another. This is achieved in the "Parameters" menu. By providing the parameters related to the open view angle, the polar angle of the viewer in the world coordinate system and the distance of the viewer from the origin of the world coordinate, the viewer can relocate himself/herself according to the information provided. Section 3. Displaying the 3-D Images The 3-D image can be displayed in various forms. In the inactive mode discussed below, only a wire-frame of the object can be displayed. In the active mode, there are few options for the viewer that can be chosen to see different aspects of the object. These options are chosen in the "View" menu under the item "Options" (a sub-menu). By activate the object(s) the viewer is interested to observe, various effects can be shown. To display all images in the current session, the viewer can click either the "Display All" item in the "3D Models" menu or the "Redraw" item in the "View" menu. This is useful in case the viewer want to see the effects of certain operations performed by him/her on the images. There are also some useful drawing actions under the "Draw" sub-menu of the "View" menu. Section 4. Object Modes An object in the program has two modes. The first one is the inactive mode in which most of the operations on it have no effects except those related to the viewer's motion (walk, shift focus, flying and zooming). The second one is the active mode in which all operations apply to it. Should you find some operations to be not effective on the object you try to manipulate, you may have had not make it active. There are three ways of turning an inactive object active. The first one is click the "Select Models" item in the "3D Model" menu. After the viewer do that, a rectangular gray mesh that bound the image appears. Clicking the mouse button 1 while locating the mouse pointer inside the mesh will change the mode of the object, namely, a active object is turned into inactive and vice versa. The second way is to click on the "Select All" item in the "3D Model" menu. The action turns every one of the objects on the screen active. As an alternative of the above two, you can first locate the mouse pointer on the object(s) interested, double click the mouse button 1. The object under the mouse pointer changes it mode after that. If you click the mouse button 1 when the mouse pointer points to the common region of several objects, each one of them changes its mode. In the inactive mode, an object has a color of darkblue. Only its wire frame is displayed. In the active mode, an object is "brightened" when it is displayed in the wire frame form. In addition, the hide hidden line and surface opera- tions can be applied to them. Also, body coordinate of an object can be displayed. Section 5. Coordinates 1.) A world coordinate that gives the viewer a sense of direction (but not the absolute location) can be drawn. It is always located at the focus of point (on the screen) of the viewer. 2.) A "body coordinate" for each individual objects can be drawn. 3.) A "bounding box" for each individual objects can be drawn with or without the numerical values of the coordinates be shown. The numerical value is related to the world coordinates of the object. The body coordinate can also be shown in the future. 4.) A solid "bounding box" for each individual objects can be drawn with or without the numerical values of the coordinates be shown. Section 6. Editing This part remains to be developed further. Section 7. Destroy and Cleaning Up Some or all of the objects created can be destroyed by following the following procedure. First activate the object(s) that is (are) intended to be destroyed, and deactivate other object(s) that is to be kept. Clicking on the "Destroy" item in the "3D Models" menu will deallocate the memory allocated by the active object(s) and therefore destroy it (them). In case all of the objects in the present session is not needed, the viewer can simply click the "Clear All" item in the "3D Models" menu. This action will free all of the memories allocated for the 3-D images.