How to use CDR expression techniques in product design This paper expounds how to use Coreldraw in the teaching of expression techniques, so as to cultivate students' ability to draw accurate drawings of products and create new products from scratch. Because Coreldraw's positioning is illustration typesetting software, not for product design and development. If you want to use it in product drawing, there are still many tricks and methods to overcome.
This paper explains the learning process and the characteristics that should be paid attention to in a step-by-step way, and illustrates with a case that if the designer has the general concept of vector drawing software and the foundation of graphics and sketches, then the concept described in this paper can be quickly transformed into the ability to draw product drawings out of thin air, and even beginners can draw quite beautiful product renderings after a period of basic training. This teaching experience is provided for interested learners as a reference.
1. Introduction
Design expression ability is an indispensable tool for developing an idea or a product, and it can also provide us with a visual representation of the reaction and evaluation of the idea (Arends, 1988). Product sketch is the most important communication medium of performance design, which aims to clearly express the appearance characteristics of products.
At present, the application of computers in drawing is quite common. In view of its convenience and good simulation effect, the works completed by computer drawing are used as the final design scheme in industry and practice, and are presented in the form of perspective view, front view or CAD dimension drawing according to different product types.
In design practice, plastic injection molding and assembly products are more suitable to be drawn by Coreldraw, which is more than enough if not involving too many three-dimensional surfaces. Other advantages include small file size of vector software, output of drawing files with various resolutions and sizes, and appreciation of drawn objects. In addition, it supports various image files, such as. Ai,. Adobe's EPS format, Photoshop PSD, and Falsh. Macromedia's SWF and SVG are quite flexible for other applications of subsequent drawing.
At present, teaching books that use Coreldraw to draw product performance diagrams are often too simple, or do not consider product design drawings (Li Junyan, 2002), which makes it difficult for interested learners to understand the key points of learning.
Therefore, this paper proposes a five-stage learning scheme, namely 1. Outline drawing, 2. Progressive coloring exercises, 3. Use of reconciliation tools, 4. Case drawing exercises, and 5. Product design is made out of nothing, and the possible problems and tricks in each stage are explained.
According to the author's teaching experience, as long as he can learn some tricks, flexibly use several Coreldraw instructions and observe the shape and light and shadow changes of general products, anyone can quickly get started and draw realistic product drawings. Take the junior college students instructed by the author as an example. In about half a semester, they can quickly master the skills needed in the case drawing stage and cultivate the design foundation out of nothing.
In addition, the course itself combines and extends the application of sketch and graphics at the same time, which is of great help to cultivate the concepts of light and shadow, three-dimensional map and three-view transformation.
2. Outline drawing
Line drawing principle, because the general product appearance is mainly geometric lines, so try to draw with geometric line drawing tools such as circles and polygons, and draw the correct shape with three shaping tools such as trimming, welding and intersection. If there is a diagonal line or curve, draw it with Bates curve.
Designers should practice drawing outline lines with the least number of nodes, and pay attention to the sharp or circular changes of lines at the shape turning point (dragging with the left mouse button can make nodes produce curvature control rods in the process of drawing Bezier curves), so that they can draw with the closest node attributes at the beginning and avoid too many subsequent modifications. At the end of the contour line, you need to close the head and tail of the node to make it a whole, which is used to fill the color or gradient.
Beginners usually can't draw the correct outline once. At this point, you can use shapetool to select a node, adjust the curvature lever of the node, or right-click the node editing tool. Seven ways (add, delete, straight line, curve, sharp point, smooth and symmetrical) are used for fine adjustment (as shown in figure 1, as shown in the left figure), so that the lines drawn by beziertool can
This part needs intensive practice to master the subtle changes of lines, and it needs to accurately describe the appearance and avoid interference.
Figure 1: Point B interference of the left curve in the above figure. When drawing with Bates curve, if the shape transition changes greatly, the lines will overlap because of excessive curvature. At this time, you can use the node editing tool to change the attribute of point B to "sharp corner", and readjust the curvature control lever to correct the result at the lower left of the above figure. On the right side of the above picture is a case of outline drawing practice. From geometry to curve, from simple to complex, the painter needs to practice and judge how to construct the outline accurately.
When drawing contours, the most important thing is to know what kind of node attributes and curvature control should be used to smooth them and make the drawing process efficient, thus reducing the editing time. Beginners can import some pictures or line sketches, practice drawing with Bates curve, and be familiar with line control (as shown in figure 1 right).
3. Gradient color filling exercise
The control of gradient color filling is an important factor to make the product stereoscopic. Coreldraw only provides four color filling methods: linear, radial, conical and square, but by adjusting the horizontal and vertical positions of the gradient center point and the rotation angle, it can match the "two-color mode" or "custom gradient" mode.
Take Figure 2 as an example. From left to right, there are circular, straight, straight, monochrome and conical filling effects respectively. The difference between the top and bottom is to adjust the way the gradient changes, which can present different textures. Square filling is rarely used, so it is not illustrated. If a designer has a good sketching ability, he can generally understand its meaning quickly and show a proper three-dimensional sense. The trick here is to assign a gradient, which can be named in the "preset effect" of the dialog box, and press "+"to save it, so that you can enjoy or modify it later if necessary.
Figure 2: Different gradient color filling methods. This exercise is used to master the skills of gradient color filling.
4. Use of reconciliation tools
The application of InteractiveBlendTool is the key to draw beautiful and realistic product drawings, and its change is also the most complicated. It has three purposes, one is to make the R angle of the product drawing, the other is to display the radian change of the surface, and it can also be used to copy and draw complex small details such as cooling holes or grids in arrays.
Usage 1: Make an R angle, and use the interactive reconciliation tool to reconcile the shapes and colors of the two squares with different colors on the left in Figure 3, so as to produce an R angle similar to a dice. As shown in Figure 3, there are 20 layers in the mixing process, and then use the selection tool to select the graphics in the mixing process, so that the outer frame is not filled with color (the faster way is to press the right mouse button on the color ticket "S" (not filled with color), and you can get the light and shadow change on the rightmost side similar to the R angle of the dice edge.
In addition, it should be noted that the number of nodes and relative positions of the two graphics that need to be reconciled should be the same (so they are all scaled, adjusted nodes and changed colors after copying the original image), otherwise the reconciliation will be uneven or disorderly.
Figure 3: An example of making R angle with harmonic tool. The gradient that forms the R-angle effect is actually composed of 20 color blocks from dark to bright, as shown in the enlarged part of the above picture.
In addition, take drawing a metal cup as an example (as shown in Figure 4), which is a combination of gradient color filling and mixing technology. The left side of Figure 4 is the finished product drawing, the disassembled drawing of each part in Figure 4, and the right side is the color block wireframe. It should be noted that basically all parts of the product must be blended at an angle of R, while the upper and lower parts of the cup body are filled with gradient colors first, and then blended with gradient blocks and black blocks at the bottom. The collocation of gradient colors and harmonic tools is the most important and commonly used skill in 3D light and shadow drawing, and you must be quite familiar with this collocation method when drawing.
Figure 4: Example of combining gradient fill and blending tools
Usage 2: Express the radian change of the surface. Take the drawing of the top view of goggles as an example. It shows the radian change of the surface (as shown in Figure 5), and produces a three-dimensional light and shadow effect through the fusion of different wireframes. As mentioned above, the number and relative position of nodes of two mixed graphs should be the same. If the designer finds that the light and shadow do not match the desired feeling after executing the Blending Tool, he can use the Shaping Tool to select any one of the upper and lower shapes.
There is an important concept about frog mirror light and shadow in Figure 5. If there are three objects, A, B and C, they can be reconciled in the order of A and B, and then B and C can be reconciled. In this case, the eye mask and the front mirror are made up of three objects, which can produce richer and more realistic light and shadow changes.
Fig. 5: an example of surface curvature change, which is characterized in that the eye mask and the front mirror part are reconciled by three objects.
Usage 3: Array copy (refer to the example in Figure 6). When designing cooling holes or complex patterns, you can first reconcile from big circle to small circle, then set the number of reconciliation processes (5 in this example), and then select the figure of reconciliation process. Press the right mouse button to split reconciliation group first, then select Dissolution Group once, and then select all circles after making sure that all circles are independent.
It should be noted that the two objects to be reconciled must be a single group with the same attributes (that is, the number of nodes is similar to the relative position). If another group is already included in the group, it will be found that it cannot be reconciled, which is why all circles after reconciliation need to be blasted first, and the group in the previous process is dissolved.
Figure 6: An example of drawing a round hole in an array with the reconciliation tool.
5. Case tracking exercises
In practical teaching, if you have the above basic concepts, you can use 1: 1 case diagram for further practice. This part takes Sanyo mobile phone in Figure 7 as an example, and beginners can complete it in two hours.
Figure 7 shows the original picture file of the mobile phone from the scanned directory at the top left, and the fine picture drawn from coreldraw at the top right. The diagram shows the separation diagram of each part drawn in the process, and the original frame diagram before reconciliation is displayed at the bottom of the diagram.
Before drawing with coreldraw, the first step is to analyze the light and shadow changes of the original drawing file (for example, the largest area of the mobile phone fuselage is actually filled with a circle, and most of the others are filled with a straight line+angle changes), and plan how many objects to disassemble, which can be directly mirrored and copied, and then drawn from large to small, from the fuselage to the details of parts. If it can effectively follow the correct procedure, it can.
Figure 7: Drawing Practice-Take the mobile phone as an example.
Using 2D software to draw 3D effect is actually deceiving the viewer's eyes by using the phenomenon and illusion of visual generalization, just like the effect of parting line or axis in this case. In fact, a black line and a light gray line are arranged side by side, and the thickness is set to 0.2 mm When viewed or printed in normal proportion, the effect is very similar to the dividing line.
Using zoomtool, you can enlarge the graph to a small place for drawing. When it is restored to its original proportion, the eyes can't distinguish it at once, so it will look very realistic at first glance. In addition, the color part is also the focus of learning. Because the surface of the product is full of colors, the painter can use the eyedropper tool to absorb the deepest and lightest colors in the original picture, remember their RGB values, and enter values in the gradient custom fill color, so that very similar color changes can be deployed.
The way of drawing enlarged pictures and drawing with straws is beyond the reach of traditional hand drawing. So even if the hand-drawing ability is not good, you can use this skill to make up for the shortcomings of technical ability, and even beginners can draw good fine drawings (refer to the student works in Figure 8 to Figure 10, with the original scanned file on the left and the Coreldraw tracing results on the right).
But to tell the truth from the original picture, the painter should not only carefully observe and consider every detail of light, shadow or shape, so as to choose the most efficient way to express it, but also test the painter's ability to draw inferences from others and create infinite effects by using limited instructions.
Figure 8: Student Works: Zhi Ming Institute of Technology has three royal titles.
Figure 9: Students' Works: There are three in Vocational and Technical College.
Figure 10: Student's Works: Zhi Ming Institute of Technology established the May 3rd General Office.
6. Product design out of thin air
Before further designing the product, let's practice a simple case. Figure 1 1 shows the side sectional view of the four buttons. Can you use coreldraw to draw a top view in an imaginative way?
Figure 1 1: Side sectional view of four buttons.
If you have skillful gradient and harmony skills, plus a little sketching and spatial ability, you can draw the result as shown in figure 12 for reference only. According to the individual's assumption that the light source position is different, the drawing method may be different. You can also think about how to show the effect of the button being "pressed".
Figure 12: Use coreldraw to draw the top view of the buttons in figure 1 1.
The above cases illustrate the design principle of making something out of nothing, that is, when drawing the appearance of a product, it is necessary to judge what gradient and harmony to present under the assumed light and shadow conditions. Designers should not only have sufficient sketching ability and graphic foundation, but also create realistic light and shadow changes and correct three views.
It is also necessary to add rich imagination and aesthetic judgment to construct a product representation with a sense of design, which is also the key ability to become a mature designer. The time required for learning varies from person to person, and designers still need to observe and practice more to control it at will.
Using Coreldraw to draw product drawings out of thin air is usually represented by orthographic view, but the perspective view is too complicated because of light and shadow, so it is not recommended to draw with this software. There are two tips in this section. One method is to draw a box with an R angle. First, draw a box with geometry tools. Then, after clicking shapetool, select any of the four corners of the box. After dragging, you will find that the R angle will be generated automatically, and radii of different sizes will be generated according to the dragging distance. If it is a square, it will eventually become a circle.
Then the fillet object is transformed into a curve, and then the required shape is modified according to the node editing tool proposed in the first stage. It should be noted that when something is made out of nothing, the vertical, horizontal, radian and leading angle of the line should be neat, and the aligned parts should be arranged neatly (especially the left-right or up-and-down symmetrical parts).
In addition, the way of coloring and color planning is very different from the above case diagram. In the process of drawing out of nothing, it is necessary to deal with color filling, gradient and harmony in a gray scale (that is, 256 steps from black to white). After the overall modeling is completed, draw the outline of the part to be colored, fill in the required color, move the color block layer to the top layer, and then use the lens tool. Set the effect of the color block to "Addcolor" or "Transparency", which can adjust the color system required by the main product and modify the color conveniently for color planning.
Otherwise, if the color has been set at the beginning, it is necessary to readjust the coloring one by one to change the color of the product, and designers should pay special attention to this difference.
Coreldraw design out of thin air has been used in the industry for a long time. In general design cases, the appearance design of products often has many restrictions, such as matching existing parts, covering existing machine cores and devices, changing panels or shapes, etc. At this time, it is quite appropriate to draw the product performance diagram with coreldraw. According to the product size, drawings (A0~A4) with different sizes can be set in the computer for drawing, and the precise size can be made by a ruler, and the output is 65438.
Although dimensions can also be marked in coreldraw, because 1: 1 has expressed the characteristics of CAD dimension drawings, it can be entrusted to institutional designers to set up the drawing files in the background, so as to establish a parametric solid model for later mold development.
Once you are familiar with Coreldraw design, you will find that this design creation method will become fast and efficient. The author thinks that for most "box-shaped" products, concept development will be faster than 3D modeling, and it can also show the subtle features and texture of real products. In addition, don't ignore that the product is composed of three elements: shape, color and texture (Lin Chonghong, 1998), Chen et al.
The author observed that if students learn 3D modeling software such as Rhino and 3Dmax directly from the beginning to draw product drawings, they will easily ignore the changes of scale, texture, pattern, tiny surface depressions and protrusions, the effects of parting line, draft angle, Logo and pattern, or ignore the buttons arranged in the interface plan, but these factors are often the key to the quality of product design.
This situation is just like the design of the chassis, which seems to be a square fuselage, but the key points that can distinguish products are often the interface layout, texture, color and other very delicate parts. These problems will become simpler and more efficient when drawing with coreldraw.
Figures 13 to 15 show the design service center of Zhiming Institute of Technology, which helped HP design and develop a small UPS cabinet. Take these three figures as an example. At first glance, they are all square, but they are different because of the above details. It is difficult to clearly show the shape characteristics when designing with hand-drawn lines or 3D methods.
How can Cdr draw a simple illustration 1? Double-click CorelDRAWX8 to create an A4-sized document. First, use Bessel tool to sketch the cartoon characters' heads, and use shape tool to adjust the inaccurate places.
2, the same steps, draw the cartoon image you conceived. This process is actually the ingenious application of Bessel tool (pen tool). Of course, you can also use similar graphics to tune, as long as you can achieve the best effect.
3. Fill the closed paths with colors respectively.
4. Finally, adjust the order of the objects with the help of Ctrl+Home/Ctrl+End, then select all, and press F 12 to adjust the expansion value and angle value in the calligraphy bar at will, so that the outline will change in thickness, as shown in the figure.
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