Technical drawing of the model, engineering graphics. Technical drawing. Methodological recommendations for students of all areas of training studying the discipline “Descriptive Geometry and Engineering Graphics. Rectangles and squares

14.04.2019

To simplify the work of making visual images, technical drawings are often used.

Technical drawing- this is an image made by hand, according to the rules of axonometry, observing proportions by eye. In this case, they adhere to the same rules as when constructing axonometric projections: the axes are placed at the same angles, the dimensions are laid along the axes or parallel to them.

It is convenient to make technical drawings on checkered paper. Figure 70, a shows the construction using the cells of a circle. First, four strokes are applied on the center lines from the center at a distance equal to the radius of the circle. Then four more strokes are applied between them. Finally, draw a circle (Fig. 70, b).

It is easier to draw an oval by inscribing it in a rhombus (Fig. 70, d). To do this, as in the previous case, first strokes are applied inside the rhombus, outlining the shape of an oval (Fig. 70, c).

Rice. 70. Constructions that facilitate the execution of technical drawings

To better display the volume of an object on technical drawings hatching is applied (Fig. 71). In this case, it is assumed that the light falls on the object from the top left. Illuminated surfaces are left light, and shaded ones are covered with shading, which is more frequent the darker the surface of the object.

Rice. 71. Technical drawing of a part with shading

What is the difference between technical drawing and axonometric projection?
How can you identify the volume of an object in a technical drawing?
Draw in workbook: a) axes of frontal dimetric and isometric projection (following the example in Figure 61); b) a circle with a diameter of 40 mm and an oval corresponding to the image of the circle in an isometric projection (following the example in Figure 70).
Complete a technical drawing of the part, two views of which are given in Figure 62.
As instructed by the teacher, complete a technical drawing of a model or part from life.

How are ideas for new models born? It's different for everyone. Some are inspired by their favorite films, others by glossy magazines, others by the colors of nature. But no matter what inspires fashion designers, all their ideas that are born in the creative process find their expression in artistic sketches of new models.

This is natural, because in order to begin the process of pattern modeling, you need to think through each new model down to the smallest detail - silhouette, design solution, color and texture of fabric, finishing - everything affects how the finished product will look. At the stage of creating an artistic sketch, you can make any changes to the product, experiment with color, length, show your imagination, give freedom to creativity, imagination and create a real masterpiece!

Advice! Keep a separate album for your artistic sketches and sketch all new ideas in it.

Keep a separate album for your artistic sketches and sketch all new ideas in it. Even if some of them do not find instant implementation, none of the sketches should be thrown away, because they may be useful to you in the future. When adding new models to the album, sometimes return to previous, unrealized ideas. Perhaps, after some time has passed, you will look at them in a new way and bring them to life.
And now a few words about what an artistic sketch should be.

What is an artistic sketch of a model?

You can first do a rough sketch or rough sketch to get your idea down on paper. It may be unclear, disproportionate, and lacking precise drawings. These are the germs of an idea First stage, when you can depict a flight of fancy as you consider necessary, understandable only to you. Experiment at this stage without limiting yourself in anything.

Rice. 1. Fore-sketch of a dress

This is followed by the creation of an artistic sketch of the model.
An artistic sketch of a model is a drawing made using any drawing technique. You can use gouache, watercolor, colored or single-color pencils, felt-tip pens and whatever is at hand for drawing. An artistic sketch is performed on a figure in an arbitrary pose. The main thing is that the model you draw conveys the mood, matches the image you have in mind, is aesthetically pleasing and comfortable to wear. All this needs to be thought through at the stage of creating an artistic sketch.

Rice. 2. Artistic sketch of the model - watercolor, ink

Rice. 3. Artistic sketch of the model - graphics

After completing the artistic sketch, it must be converted into a technical sketch, according to which it will be necessary to model the patterns.

Technical sketch of the model

A technical sketch of a model is a drawing of a product on a conditionally standard figure, with a clear definition of all the design features of the model, using a grid of base lines - the base of the neck, chest, waist, hips, central axis. This will allow you to make a more accurate calculation of the location of structural seams, parts, pockets, etc.

Rice. 4. Technical sketch of the model - front and back

Make yourself a rule: always accompany the technical sketch of the model detailed description and calculation required quantity fabrics and applied materials for its sewing. This will greatly simplify your work and allow you to more accurately estimate the cost of the finished product, make it possible to optimize the modeling and cutting process and obtain a more accurate result. But this is exactly what we strive for!

In the description of the technical drawing of the product, be sure to indicate the following parameters:

1. Short description free form products.
2. Silhouette, product design features, size.
3. Calculation and description of the required amount of fabric for the product.
4. Description and calculation of the required quantity additional materials for the product (gaskets, fittings, threads, etc.).
5. Features of the model.

Rice. 5. Description of the technical drawing

If artistic sketches, as mentioned above, are best sketched on landscape paper, a squared notebook is ideal for technical drawing. In it you can easily enter a technical sketch and fill out a table describing the model.
After you have done all preparatory work and create a technical drawing, it will be much easier for you to create a basic pattern for the product and develop patterns.

Ready-made templates for your sketches

Rice. Art sketch template

And now - the fun part! We have prepared for you a template with silhouettes of female figures for artistic sketches on A4 format. Just download the pdf file, print it on a black and white printer and draw your sketches directly from the silhouettes.

This way you won’t have to waste time drawing the figures - after all, we’ve already drawn them for you! By the way, ready-made sketches very convenient to store in a binder.

Unlimited creativity to you!

Publishing house of Altai State Technical University

Reviewer: Candidate of Technical Sciences, Professor of the Department of MRSiI BTI AltSTU

Svetlova, O. R.

C24 Technical drawing: guidelines for students of all

areas of training studying the discipline “Descriptive Geo-

geometry and engineering graphics" / , ;

Alt. state tech. University, BTI. – Biysk: Alt Publishing House. state tech. University, 2012. – 16 p.

The methodological recommendations present theoretical material, visual material on drawing techniques geometric shapes and details from life. Guidelines are intended for students of all areas of training studying the discipline “Descriptive Geometry and Engineering Graphics”, all forms of education.

Reviewed and approved

at a meeting of the TG department.

Protocol No. 74 of 09.28.11

INTRODUCTION……………………………………………………………………………….
1 TECHNICAL DRAWING…………………………………………..
1.1 General information about the drawing………………………………………………………..
1.1.1 Observational perspective……………………………..
1.1.2 Chiaroscuro…………………………………………………...
1.1.3 Proportions…………………………………………….
1.2 Working with a pencil……………………………………………………………………
2 PRACTICAL LESSONS…………………………………………………………….
LITERATURE……………………………………………………..

INTRODUCTION

Purpose of technical drawing. Technical drawing, like axonometric projections, serves to construct visual images of models and parts.

Technical drawing differs from axonometric projection mainly in that it is performed without the use of drawing tools(by hand). In technical drawing, parallel (axonometric) perspective and the same projection axes (coordinate axes) are used.

Technical drawings give a visual representation of the shape of a model or part; it is also possible to show not only appearance, but also their internal structure by cutting out part of the part in the directions coordinate planes. IN practical work drawing serves as one of the important means of conveying a technical concept.

1 TECHNICAL DRAWING

A realistic rendering of the image of an object in a drawing is achieved using observational perspective, light and shade and correct proportions.

For greater clarity, technical drawings include shading, shading or scribbling shadow sides parallel to some generatrix or parallel to the axes of projections (Figure 1).

Picture 1

Shading is called shading made in the form of a grid. To determine the degree of darkening of a particular surface, the following types of shading can be taken as a basis:

- dark surface– the distance between the strokes should be 2–3 times less than the thickness of the strokes, or the shading should be replaced by scribbling;

- penumbral surface– the distance between strokes must be equal to the thickness of the strokes;

- light surface– complete absence of strokes or sparse shading.

Drawing- this is a graphic image of an object on a plane, conveying it as we see in reality. The ability to draw competently is necessary for workers in many fields of science and technology. Drawing promotes the development of spatial thinking, visual memory, creativity and artistic taste. Mechanical engineering technologists must not only be able to read blueprints, but also draw objects correctly and quickly, as they come across a variety of product shapes, sizes and finishes.

The parts of machines and machine tools basically resemble various geometric shapes (cylindrical, conical, prismatic). The study of images of these forms is based on the study geometric bodies. Therefore, in technical drawing it is given great place drawing various models.

1.1 General information about the drawing

In a realistic drawing, three-dimensional objects around us are depicted as they really exist and as our eye perceives them.

A realistic rendering of the image of an object in a drawing is achieved through the use of observational perspective.

1.1.1 Observational Perspective

The perspective method makes it possible to depict three-dimensional objects based on visual perception nature. Structure human eye can be compared to the device of a camera. The refractive medium of the eye, like its lens, is mainly the lens located behind the iris. The image obtained in a photograph is similar to the image on the photosensitive retina of our eye.

When drawing from life, the rules of linear (central) perspective are applied. The perspective construction of objects in a drawing is done by hand by eye while observing the depicted object. This is why this perspective is called observational. All objects, as they move away from the eye of the drawer, seem to decrease in size, and parallel lines actually appear to converge at a certain point or points. Hence the rule: all outgoing horizontal lines going to the horizon line intersect on the horizon line at one or more vanishing points (Figure 2).

Perspective horizon line called a conditional straight line located at eye level of the drawer.

Outgoing horizontal lines are called horizontal lines that move away from the person drawing. The perspective horizon line divides the visual world in half - into the world seen from above and the world seen from below.

Figure 3 shows two cubes - one below the horizon line, the other above the horizon line (eye level). It can be seen from the figure that the outgoing horizontal lines of the lower cube are directed upward, towards the horizon line, and the outgoing horizontal lines of the upper cube are directed downwards, also towards the horizon line and intersected at one vanishing point. The bottom cube shows the top edge, and the top cube shows the bottom edge.

Figure 2

Changing the point of view and eye level (horizon line) changes the perception of the world around us. For example, there are three cubes in space, they are located at different heights in relation to the horizon line and our view (Figure 4). One cube is above eye level, we see its three faces - the bottom and two sides. The lower cube is below eye level and to the right of the upper one, we also see three faces, but instead of the lower base we see the upper base. The width of the edges is perceived differently. In the upper cube, the right side seems wider; in the lower cube, the left side appears wider, since they are turned more towards the viewer. In the middle cube we see only two faces; it is crossed by the horizon line. The construction of a cylinder in space is shown similarly in Figure 5.


Figure 3	Figure 4	Figure 5

Technical drawing begins with the construction of projection axes, which are done by hand.

1.1.2 Chiaroscuro

Chiaroscuro plays an important role when depicting a three-dimensional form. The distribution of light on the surface of an object has a certain pattern (Figure 6), which depends on the shape of the object, the nature of its surface, its color, lighting, the distance of the object from the viewer and the condition environment. On the surface of bodies of rotation there is a smooth transition from light to shadow; faceted bodies have sharper shadow boundaries than round ones. You need to start shading from the darkest places, having first checked the perspective of the drawing. In their own shadows they distinguish more bright places – reflexes, resulting from highlighting one’s own shadow with part of the light rays reflected from neighboring objects, a stand, a table. On objects with a shiny or transparent surface (metal, glass), glare – sharply limited areas of the surface of an object, from which greatest number reflected rays of light enter the painter's eye. They are most often observed on convex objects or folds.

Figure 6

By maintaining the correct light and shadow relationships in the drawing, you can convey not only volumetric form object, but also their different colors and textures of the material. The drawing must correctly reflect the light relationships of natural surfaces.

1.1.3 Proportions

To determine the size of the faces, we use the sighting method. At arm's length, with a horizontal pencil, measure the width of the left side of the cube, then the right side, determining which one is larger and by how much, set aside the required dimensions (Figure 7).

Figure 7

When drawing bodies of revolution and polyhedra, the width of the bases in the image depends on the degree to which they are removed from the horizon line. The closer the base is to the horizon line (eye level), the narrower it will be, and the further the base is from the horizon line, the wider it will be. The base coinciding with the horizon line will be a straight line (see Figure 5).

1.2 Working with pencil

They begin the drawing with thin, inconspicuous lines, and then, when the composition of the drawing is correctly decided and the proportional relationships of the subject are found, they gradually refine the lines and enhance the tone.

Figure 8 shows the step-by-step construction of the figure. When starting to sketch a model or models, you must first mentally follow the direction of each line of the model, and then put it on paper. If the line is drawn incorrectly, then it is not erased, but another, or a third, more accurate one is drawn. Initially, inaccurate lines drawn during construction are almost not visually perceived in the drawing. At the stage of completing the drawing, they are absorbed by the overall tone of the drawing.


Figure 8

To make a training drawing, a simple graphite pencil of medium and soft hardness (TM, 2M, 3M) is used.

Rubber (soft) should be used as little as possible, using it mainly for highlighting tones, reflex or glare. Drawing strokes is a means of conveying light and shade in a drawing. Intensification of tone is achieved by repeatedly covering the surface of the paper with strokes in various directions, as well as changing the pressure of the pencil.

The nature of the strokes depends on the shape of the object. To depict flat surfaces, rectilinear strokes are usually used, and curved strokes are used to depict curved surfaces. When choosing strokes, take into account the texture and material of the objects. Distant objects, objects with a smooth surface, as well as the background are covered with light strokes or shaded.

2 PRACTICAL LESSONS

When performing tasks, it is necessary to take into account the lighting of objects. In all exercises, light falls on objects from left to right, from top to bottom. Only the product's own shadow is performed without taking into account the falling shadow.

Exercise 1. Cube drawing.

Instructions for implementation are in Figure 9. Examples of implementation are in Figure 10.

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