3. Basics
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3. | Basics | |
This chapter addresses CAD beginners as well as CAD experienced users. Later on, in chapter 4, we will deal with each drawing function in detail. And then, these basics here will support the learning of handling CYCAS.
Scale : You can create a drawing without setting a scale in advance. All elements are entered 1:1. The (drawing-) scale is necessary to display text, figures of dimension chains, and the different line types correctly. This means, you start drawing without worrying about the scale. When you come to the point where you want to add text and dimension chains to your drawing, you choose the drawing scale. It is chosen at the menu Project. Coordinate system : Mainly, a planar cartesian coordinate system is used. The positive X-axis extends horizontally to the right and the positive Y-axis extends vertically to the top. Entering 3D the Z-axis is added and defines the hight of the elements. The drawing area itself is a plane of infinite dimension. So you are working in a certain part of the drawing area at a time. Coordinates are usually specified relatively. Watch the coordinate display and place the start point of a line. Now move the mouse and see how the coordinates are measured relatively to the point you just have placed. Snap-to : Within the snap-to box start points, end points, points of intersection, etc. are caught with full accuracy. CYCAS gives you a hint displayed in the snap-to frame what could be caught at the current position of the cursor. (For details on this, refer to 2.2 Mouse pointer.) Did you snap-to such an existing point with full accuracy, it is signalized by a little circle added to the cross. The snap-to is important to achieve the desired accuracy of a CAD drawing. Later on, when entering dimension chains you will take full advantage of accurately entered elements. Doing the measurement you snap-to the points of the elements again and those distances will be calculated and displayed in the figures of the dimension chains. Keyboard input : You will achieve an accurately drawing easily by using the keyboard input in combination with reference points. Keyboard input is made below the drawing area. (Please also refer to the Tutorial, Window.)
Angle input : There are two possible ways to enter an angle; the first is to enter a numerical value in degrees or radians (see Appendix, section 8.1 Settings, Input.) All angles are measured counter-clockwise with the positive X-axis describing an angle of zero degrees. The other way is, to describe the angle using a directional line. This is an imaginary line that describes the desired angle using two points (called direction points).
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3.1 | Entering points | |
The method of entering points in CYCAS is following the method of drawing on a conventional drawing board.
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3.2 | Dialog boxes | |||||||||
The dialog boxes are used to set certain options for the drawing elements. Every type of element provides a dialog box which contains different sets of options.
The settings you make in the dialog boxes during the course of a project can be named and saved separately. These data can be handled on a per-project basis, since a draft requires different settings than a presentation. (See the appendix 8.1 Settings, Local.)
Dialog boxes are available for these elements:
Choose Wall from the main menu. The wall function list contains a button labeled ?. Click on this button to open dialog box. You can make as many settings as you wish, name them and save them. The name of the current dialog box will appear in the function list behind the ?. There, you can choose a different dialog box and continue drawing with these new settings.
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3.4 | Snap-to and guide functions | |||||||||||||||||||||||||||||||
The snap-to and guide functions effect the input and the editing of drawing elements. This area of the CYCAS interface also contains the Undo function and functions for the creation of guide lines. The snap-to button, the snap-to settings, as well as the construction of snap-to points are available during the creation of elements. Snap-to : If this button is pushed in, the snap-to is active and the mouse pointer is displayed as a small rectangle. Exact input is only possible when the snap-to is activated.
Preview Snap-to: CYCAS gives you a preview of what it could snap-to at the current position of the mouse. It indicates whether ending points, middle points, or points of intersection were available. Surely, you may de-activate this preview. (For details, please refer to 2.2 Mouse pointer, Snap-to points.) Within the snap-to rectangle you can snap-to these points:
Snap-to points of intersection between different elements.
The dialog box for the snap-to points is opened by clicking on the ? button next to the snap-to button. Determining points of intersection needs time for their calculation. So, you may shorten this time by de-activating certain aspects of the snap-to. This could be useful in case you are working on a very large drawing.
In addition to the snap-to we discussed so far, you can also construct snap-to points. These may be the middle point or a dividing point of a line. This could also be the tangent point of an imaginary line running towards a circle. Furthermore, you can construct points of intersection between elements that only intersect if assuming that they are of much greater length. The following functions can be called whenever entering a point. For every point you want to place in the drawing area using the mouse, you may insert the functions for the constructed snap-to points. Enter the necessary information for constructing the snap-to points. If a snap-to point is valid it is marked with a cross. After that, the input function continues as usual.
Undo : The recent changes made to the drawing can be made un-done or made re-done again. GL+ : Draw guide lines. If this button is pushed in, you can draw elements using the guide line color. When using the default settings, guide lines are displayed in pink. You can use guide lines to make notes in your drawing or to create sketches. In the Edit function list, you can change the color for the guide lines. CYCAS will not print or plot elements drawn in the guide line color. GL- : Delete all elements of guide line color on the active layer. If you wanted to keep a guide element, you can alter its pen color with the appropriate function of the Edit function list.
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3.5 | View menu - the zoom functions | |||||||||||||||
Directly below the drawing area you find all functions for moving and scaling the visible area, as well as some options for the display of elements inside this area. You can change the visible area at any point in time, even while doing the input of elements.
Gauge : Measure the distance between two points. Place two points within the drawing area, e.g. the start and end point of a line. Confirm the second point. CYCAS will open a window containing information on the X, Y, and Z-components, as well as length and angle of the distance measured. + : The scale is enlarged, while the center of the visible area remains the same.
1:500 : This button indicates the scale of the visible area. By clicking on this
button you can move the visible area without changing the scale. The cross marks
the new center of the visible area. Place it where you want the new center to be. - : The scale is made smaller, but the center of the visible area remains.
Zoom : Enlarge a certain area of the screen. Draw a rectangle around the
area which is to be enlarged by setting two points.
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3.6 | Layers | |||||||
You may compare the CYCAS layers with transparency sheets that can be put on top of each other. You work on the active layer and others can be displayed in the background. For organizing your projects 1000 layers are offered. These 1000 are grouped in lists of 100 layers each. You can name the lists as well as the single layers individually. When sending the drawing to printer or plotter only the visible layers are printed. You can move drawing elements from one layer to another by using the Symbol functions. These functions such as cut, copy, and paste can be found at the menu Symbol or at the Clipboard above the main menu.
You can snap-to all aspects of background layers. (See 3.4 Snap-to and guide functions, Snap-to.) This means that you can have parts of your design displayed in the background. This may help you working on the active layer. Parts can be counter drawn or simply taken for orientation. When selecting, elements in the background remain uneffected - unless you explicitly activate the altering of the "Visible Layers".
Create your drawings, e.g. a house, one floor at a time. Draw the basement on the first layer and name the first layer accordingly. Draw the first floor on the second layer and put the basement layer in the background. Now, you can "carbon copy" all those walls of the first floor that rest on the basement walls. The offset of the first floor walls to the basement walls (if there is any) can be determined using reference points. The next step would be to use the fourth layer for the section. Put the first floor plan in the background and draw the section. Put the top floor on the third layer. Here you could again put the first floor and the section in the back. Finally you can use the fifth layer for the different views. You e.g. could put the section in the back and draw the gable views. The eaves views could also be drawn on the fifth layer and the eaves and ridge heights can be projected from the section or the other views. Place parts of the drawing that re-appear in other plans on different layers, e.g. the plan head. Create a layer that contains the plan head and put it in the background of the other layers - remember, all visible layers will be printed or plotted. Another application would be to use one layer for every step of a project. You could put the measurements or the patterns on separate layers. This would speed up the display as the measurements and/or patterns would not always have to be visible. You could even maintain an entire project in only one file by using different layers for the draft and the final plans. You could e.g. create the plan on one layer and put the appropriate dimensions and text in the back, depending on which phase your project is currently in. 3D-data that is to be passed on to raytracing or shading programs can be distributed over several layers on a per-unit basis. Use different layers for walls, ceilings, stairs, stair rails or the roof construction. This allows you to edit the elements easily for you cannot alter the elements of the background layers accidentally.
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3.7 | Polygons | |||||||
A polygon must have at least three points and it must be closed.
Polygons out of splines: If you snap-to start points and end points of a spline CYCAS will recalculate the form of the spline for the polygon.
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