Unbridgeable gap between evolution of blue-print codes and communication – paradigm changing in production

The traditional 2D drawing (hand drawing) in engineering has a commonly known communication code. These communication codes (type of line, width of line or other marks) makes the engineering communication easier, faster and safer. In the last couple of decades new computer aided design and manufacturing methods have been developed. The communication has been changed. This article aims to investigate the gap between software development and rules of communication. Although software support has developed the communication codes and basics have not been significantly changed. 2D drawing code is not yet fully included in modern 3D CAD software. Automatic 2D drawing generation from 3D computer models results problems, for example in sections, cuts and break-outs. This paper shows the most common problems and makes recommendation through harmonisation of the communication codes.


Introduction
Description of complex shapes is very difficult.That is why technical drawings are generally accepted as a special language to describe shapes and sizes.The drawing creates a connection between the designer, the manufacturer and the operator.If the link is not cor-rect, the information cannot be passed, or can be passed incorrectly (STASIAK-BETLEJEWSKA, POTKÁNY, 2015).It is, therefore, necessary for the application of drafting standards to minimise the error in data transmission over the connection (Fig. 1).

Fig. 1. Communiaction chain in Egnieering
Source: own study As spoken and written language change drawing standards also keep evolving in times.The first graphical representations can be found in the caveman era, in the form of cave paintings The cave drawings of prehistoric man also ca tured the images of a slice of reality.By using these drawings, previous experience was called; the animal was likely to be had to be faced while hunting.Therefore, it c to overcoming fear, and provided opportuni pare for the fight.The image, thus, information.Of course, in this case it is only a two dimensional depicting, a visual display performance.A significant progress in the area of visual represent tion has been brought by Leonardo da Vinci (1452 1519).In his paintings, effort can be seen to show the Lovas, Unbridgeable gap between evolution…, Vol.12(3)/2016 23

Communiaction chain in Egnieering
As spoken and written language changes, the drawing standards also keep evolving in times.The first graphical representations can be found in the caveman era, in the form of cave paintings (Fig. 2).

Fig 2. Cave drawings of prehistoric man
The cave drawings of prehistoric man also captured the images of a slice of reality.By using these was recorded and rewas likely to be recognized which Therefore, it contributed opportunity to pre-, became source of information.Of course, in this case it is only a twovisual display performance.A significant progress in the area of visual representado da Vinci (1452effort can be seen to show the objects and shapes in three dimensions and lent application of perspective shapes are shown clearly by there is no satisfactory dimensions.

Fig. 3. The Adoration of the Magi (Leonardo)
During his whole life, Leonardo always the most accurate representation works, he used different colours to show distan depth sizes.For example shoulder of Mona Lisa; the blue colour.The section representation of technical drawings are also indebted is more, he also used the broken-up-sections and half objects and shapes in three dimensions and an excelperspective depiction (Fig. 3).The shapes are shown clearly by perspective depiction, but satisfactory information about the exact During his whole life, Leonardo always attempted representation possible.In his late he used different colours to show distances and depth sizes.For example, it is not ice able above the the farther the part, the darker .The section representation of technical indebted to Leonardo (Fig. 4).What used the modern sense of the word sections and half-sections.However, engineering applications are usually very complex structures, to represent them, Leonardo also had to choose the 3D geometry method In Fig. 5. it can be observed that he tried to pr sent the operation of the device where the mechanism and specific details can be also seen, for example gear linkage.Unfortunately, this plan could only five hundred years later.The basics of the currently used code of mechanical representation evolved in the early twentieth century.The first monochrome procedures spread by this time and the rules were adapted to them.Instead of the previous use of various colours, line colours became only black.functions were signed by various types and thickness of lines.The views are basically plane projections, the rules of revealing internal details are created for hand made drawings.This regime was used in a significant part of the last hundred years.
In the last twenty years thanks to the modern 3D CAD-systems and the rapid spread of coloured prin ing and copying the system of rules seems to become limited.(LOVAS L., 2010) Nowadays planned parts are designed by the level of the freehand sketches.They are created as a 3D model in a CAD system immediately after the development of the main topology and function (COMPANY ET.AL., whole development is done on computers, and there is no need for plane drawings for the production (CNC machines, 3D printing processes), (FICZERE 2016).The question arises: is there any need for using However, engineering applications are usually to represent them, Leonardo method (Fig. 5).
propelled cart (Leonardo) it can be observed that he tried to prethe mechanism and specific details can be also seen, for example gear only be realized five hundred years later.The basics of the currently used code of mechanical representation evolved in the monochrome copy procedures spread by this time and the rules were adapted to them.Instead of the previous use of various became only black.Different functions were signed by various types and thickness projections, the rules of revealing internal details are created for handmade drawings.This regime was used in a significant In the last twenty years thanks to the modern 3D systems and the rapid spread of coloured printing and copying the system of rules seems to have Nowadays, the planned parts are designed by the level of the freehand ches.They are created as a 3D model in a CAD system immediately after the development of the main ., 2009).The whole development is done on computers, and there is no need for plane drawings for the production (CNC ICZERE, BORBÁS, s there any need for using the conventional plane drawing rule systems?If yes, which parts of them are modern, and which parts are not worth applying anymore?A further advanta 3D models against the 2D plane drawings can be used for marketing purposes ences cheques, fit investigations (animation) and functional analysis can be made by them.Furthermore, it can also be used the loadability (numerical analysis), optimizing the geometry and material and for examinatio sembly possibility (IVANCO, K ULEWICZ R., JELONEK D., MAZUR M. 2015, ULEWICZ R. 2013, NOWAKOWSKA MAZUR M.).
First the main requirements of the drawing doc mentations will be investigated, after (it), the problems of plane drawings generated by CAD systems will be introduced.Finally, suggestions for modifying the drawing rules to the case of free CAD drawings will be given.

General Requirements About Dra ing Documentations
The main rules about planning ity and safety which means the following of technical drawings • obvious documentations technical description) • simple understandability (readability) • availability of all information dancy) • possibility of simple and quick representation in any circumstances The components and structures must be safely by the drawing, while the framed construction must be operable.In the course of modelling the generated plane dra ings can be part drafts or assembly drafts.The r quirements of these two drawing documentation partly the same and different.
The main requirement about part drafts is obv ously the manufacturability.It means verifiability and the giving the necessary views, sections, symmetries, dimensions, surface roughness, form and orientation tolerances.The requirements about assembly drafts are ings: the conventional plane drawing rule systems?If yes, which parts of them are modern, and which parts are ?A further advantage of 3D models against the 2D plane drawings is that they can be used for marketing purposes as well as interferinvestigations, motion simulation (animation) and functional analysis can be made by it can also be used for surveying the loadability (numerical analysis), optimizing the geometry and material and for examination of the as-KMET, FEDORKO, 2016, AZUR M. 2016, KRYNKE OWAKOWSKA-GRUNT J., First the main requirements of the drawing documentations will be investigated, after (it), the problems of plane drawings generated by CAD systems will be suggestions for modifying the drawing rules to the case of freehand drawings and stresses should be verifiable By creating plane drawing the above given co siderations must be observed as far as possible.

Differences Between Plane Drawings And Generated Drafts
If the component or mechanism has a 3D model, the simplest way of creating plane drawings is genera ing projections with the help of an embedded alg rithm of the applied software.It happens usually with respect to the rules of drawings.With a the rule if the component has such which have rules of symbolic simplified representation are applied to in 2D drawings: • thread, • ribbing splinedshaft and hub • gears.
In case of threads, the representation is also si plified in three dimensions (Fig. 6), with graphic memory and computational time, and the plane representation will also be simplified ET.AL., 2016, SYGUT P., KLIMECKA BORKOWSKI S.).In such cases colours are used to repr sent the features (for example the length of thread), but the solid geometry does not follow it.Splines are not simplified in projections by sof ware (Fig. 7).
Lovas, Unbridgeable gap between evolution…, Vol.12(3)/2016 25 clear definition of the relationships of joining functions of related surfaces should be obviassembled status, position should be overview, question of decidability of assembly boundary conditions (positions, dimensions, stresses should be verifiable plane drawing the above given considerations must be observed as far as possible.

Differences Between Plane Drawings
If the component or mechanism has a 3D model, way of creating plane drawings is generatthe help of an embedded algorithm of the applied software.It happens usually with With an exception to if the component has such details or features which have rules of symbolic simplified representation splinedshaft and hub, the representation is also sim-), in order to spare phic memory and computational time, and the plane representation will also be simplified (MOLNAR, LIMECKA-TATAR D., .In such cases colours are used to repretures (for example the length of thread), but follow it.At representing gearing (Fig. 8), software aim to visualize the real shape and the generated representation is not only incorrect but makes reading the drawing more difficult, especially in case of joining gears.Another problem is the usage of different se tions.Generating revolved sections which is a simple type of section, cannot case of broken-out-section the border li out also does not meet the current standard of eng neering drawing (Fig. 10) The reason of it is that modifying the default line types is quite difficult (it is possi the same time).

Projected representation of spline shaft without simplification
At representing gearing also may not be simplified software aim to visualize the real shape and the generated representation is not only incorrect but makes reading the drawing more difficult, especially in problem is the usage of different sections.Generating revolved sections which is a simple be generated automatically.In section the border line of the breakmeet the current standard of engi-10).The reason of it is that modifying the default line types is quite difficult (it is possible only in groups at This problem has been solved in the latest ve sions of software, so the border-line of broken outs appears automatically in the correct form.Marking of tangential connections does also not meet the standards because rounding should be marked with only one tangent line, not two.It is clear that the necessary details can be re resented fully, but in many cases it is much more difficult and needs more paper than a freehand drawing. In general software does not apply the rule that certain parts must not be sectioned lengthwise -mostly tight elements -to avoid mass effect such elements are for example shafts, pins, ribs, spokes (Fig. 11).
the latest verline of broken outs appears automatically in the correct form.Marking of tangential connections does also not meet the standards should be marked with only one

out-section
Rules of sections in the symmetry plane are only full-or details can be represented fully, but in many cases it is much more difficult and needs more paper than a freehand not apply the rule, that certain parts must not be sectioned lengthwise d mass effect uch elements are for example shafts, pins, ribs, In case of rod-like or shaft (hardware parts), such as pins, screws, shafts this feature can be defined which is taken into account by the CAD software.Another problem is the section of gears.In case of straight or oblique tooth, the solid model is always sectioned by the cutting plane and the simplified representation is a frequent situation that in case of teeth on the one side the tooth surface can be seen but on the other side there is a sectioned tooth.In  problem is the section of gears.In ique tooth, the solid model is always sectioned by the cutting plane and the simplified representation is not applied.It is situation that in case of odd number of teeth on the one side the tooth surface can be seen is a sectioned tooth.In case of oblique teething it is more difficult to u derstand the drawing (Fig. 8).
In case of oblique projections it is difficult represent the symmetry lines and bolt hole ci cles.Mostly in software it is not adapted therefore symmetry lines follow the horizontal and v directions of the paper (Fig. 13).

Fig. 13. Problem of representation of symmetry bolt hole circle
Source: own study.
If students study hand and software drawing simultaneously, they are inclined to accept to be correct without criticism, which they have seen on the screen.

Harmonizing Of Hand And Software Drawing Habits, Suggested Modific tions
In order to make the transition from the drawn 2D documentation to the generated 3D documentation does not pose any break neither for the designer, nor the user, if a bit late, but it would be appropriate to make recommendations to convert the machine draf ing standards, as well as the developers of CAD sy tems.
Lovas, Unbridgeable gap between evolution…, Vol.12(3)/2016 27 case of oblique teething it is more difficult to un-In case of oblique projections it is difficult represent the symmetry lines and bolt hole circles.Mostly in software it is not adapted therefore lines follow the horizontal and vertical If students study hand and software drawing they are inclined to accept to be they have seen on

Harmonizing Of Hand And Software Drawing Habits, Suggested Modifica-
In order to make the transition from the drawn 2D 3D documentation does not pose any break neither for the designer, nor the user, if a bit late, but it would be appropriate to make recommendations to convert the machine drafting standards, as well as the developers of CAD sys-Below -from our own e possibilities are emerging:

Application of colours
It is possible to use different colours for lines b side the thickness.It works at 2D software was not very successful, because it is very different from the engineering way of thinking, and from the usual code system.
Instead of hatching of surfaces, or distinction of parts it could be possible to fill the surfaces with di ferent colours inside the contours.

Application of simplificatopns
In case of threaded parts, splines and teething the simplified and realistic representation should be both accepted.At the figures of SKF threaded parts are represented in this way for decades

Application of simplificatopns
In case of threaded parts, splines and teething the simplified and realistic representation should be both accepted.At the figures of SKF threaded parts are esented in this way for decades (Fig. 14).It is also important to mention that in solid ronment the software is not able to generate section, also more sections are needed to represent each connections exactly.

Section view of assembled clutch
Then examine the result of making solid section t colours instead of standard speci-

Fig. 17. Section of a clutch in solid environment
It is also important to mention that in solid envithe software is not able to generate revolved section, also more sections are needed to represent It is visible that in case of symmetric element (for example bearings) it is specifically disturbing if that is not in the right position.
It is important to notice, although at paid to it, that the cutting plane should not cross the teeth of flywheel-ring gear, so that the teeth could be seen in view, not in section, but the teething is still difficult to interpret for computers.

Use of axonometric figures
With the use of solid CAD software views and sections are just generated, which can be prepared quite quickly.
It would be practical to prescribe to represent the solid view of the element as well on the draft, it could help in interpreting the drawing especi complex, intricate elements.

Suggested modifications for CAD software developers
On the generated drafts from the realistic 3D visualization the representation should be simplified as far as possible (threads, gear teeth, Some software (for example Solid Edge) already has the opportunity to use simplified representation, but these do not always meet the standard code of technical drawings.
The border lines of sections and broken tions should be defined and formatted It is suggested to apply this rule in case of auxi iary sectioning, ribs and gears, so that the gear teething or rib could be seen in view, independently of the pos tion of the plane section.

Summary
This paper attempted to reve lems.It is suggested to harmonize the code system of the two different ways of creating drawings within the limits of common sense and using the modern techn cal opportunities.
It is important to remark that the regulations and recommendations of standards can be different in many cases.Software must meet not only Vol. 12(3)/2016 that in case of symmetric element (for example bearings) it is specifically disturbing if that is It is important to notice, although attention was it, that the cutting plane should not cross the ring gear, so that the teeth could be seen in view, not in section, but the teething is still difficult to interpret for computers.

Use of axonometric figures
the use of solid CAD software views and sections are just generated, which can be prepared It would be practical to prescribe to represent the solid view of the element as well on the draft, it could help in interpreting the drawing especially in case of

Suggested modifications for CAD software
On the generated drafts from the realistic 3D visualization the representation should be simplified as far as possible (threads, gear teeth, etc.) Some software (for example Solid Edge) already the opportunity to use simplified representation, but these do not always meet the standard code of The border lines of sections and broken-out sections should be defined and formatted simpler.
It is suggested to apply this rule in case of auxilgears, so that the gear teething or rib could be seen in view, independently of the posito reveal the main probto harmonize the code system of the two different ways of creating drawings within the limits of common sense and using the modern techni-It is important to remark that the regulations and dards can be different in many cases.Software must meet not only European but also American and Japanese standards.It can be solved with different predefined profiles.
It should be always kept in mind that the purpose of drawings is communication.They establish the connection between people working in the planning, manufacturing, and operation phase of the product.That is why it should be strained after the most simple, clear and fast opportunities of representation.
CAD systems are not always and not everywhere available.What is more, in most cases, for example, in case of a malfunction of an element to receive its technical details its parameters and its installation environment only a monochrome pencil can be available.
Therefore, it is important to consider whether non-symbolic representation of threads, material patterns is applicable in all cases, or the conventional regulations such as hatching in different directions should be followed.
By the appearance of solid modelling systems the code system of technical drawings could be more permissive.In some cases more solutions could be permitted, but only with observing and conserving the original symbolic representation.

Fig 2 .
Fig 2. Cave drawings of prehistoric man

Fig. 5 .
Fig. 5. Leonardo's self-propelled cart (Leonardo) planning are clarity, simplicmeans the followings in the area obvious documentations (drawing, parts list, understandability (readability) availability of all information (without redunpossibility of simple and quick representation The components and structures must be creatable ely by the drawing, while the framed construction In the course of modelling the generated plane drawings can be part drafts or assembly drafts.The redrawing documentation are in requirement about part drafts is obviously the manufacturability.It means verifiability and the giving the necessary views, sections, symmetries, dimensions, surface roughness, form and orientation The requirements about assembly drafts are the follow-• clear definition of the relationships of joining components • functions of related surfaces should be obv ously traceable • assembled status, position should be overview, question of decidability of assembly • boundary conditions (positions, d

Fig. 6 .
Fig. 6.Solid representation of a screw with simplified representation of the thread (colour and rendering) Source: own study

Fig. 6 .
Fig. 6.Solid representation of a screw with simplified representation of the thread (colour and rendering)

Fig. 7 .
Fig. 7. Projected representation of spline shaft without simplification Source: own study

Fig. 8 .
Fig. 8.: Drawing of a gear without simplification of splines and gear featuresSource: own study

Fig. 8 .
Fig. 8.: Drawing of a gear without and gear

Fig. 10 .
Fig. 10.Problem of border line of broken-out Source: own study

Fig. 11 .
Fig. 11.Problem of section of tight, cylindrical part Source: own study

Fig. 11 .
Fig. 11.Problem of section of tight, cylindrical part

Fig. 13 .
Fig. 13.Problem of representation of symmetry-lines and

Fig. 16 .
Fig. 16.Section view of assembled clutch Source: own study

Fig. 17 .
Fig. 17.Section of a clutch in solid environmentSource: own study