QUESTIONS ON CAD

1. What is Geometric Modeling? Classify it.

Geometric Modeling is the process of generating three-dimensional objects of the real world for the purpose of analysis, design, drafting and manufacture.Geometric Modeling creates a database in the computer, which represents the object generated. This object database is used to display the object, to prepare drawings of the object with different views, to prepare data for analysis and design and also to manufacture the object using CNC machines.Classifications of Geometric Modeling:In general, there are three types of models commonly used to represent physical objects. They are:1. Wireframe Model2. Surface Model3. Solid Model

2. What is the advantage of surface modeling over wireframe modeling?

a) Wireframe models are the simplest among the three types of models.They are easy to create and use. They are generally used to create models of simple objects.In surface modeling, not only simple but also even complex shapes can be generated by combining Planes, ruled surfaces of revolution, sweep surfaces and fillet surfaces.

b) Surface models define part geometry more precisely, as compared to the wireframe model, and can be used directly to generate path profile data for NC machines.But Wireframe model does not distinguish between inside and outside of the surfaces of the object and they are inadequate to be used for generating cutter paths to drive NC machines to manufacture the object.

c) In Surface modeling, Techniques like hidden surface removal and hidden line removal makes it possible to display the objects as a solid object and viewed from any point.But these techniques are not available in the wireframe modeling

3. What are the different drafting standards?4. List out the various drawing sheet sizes.5. What is the use of Grid Reference System?6. What is Item Reference Number?

7. Explain briefly the following.a) Assembly Drawingb) Sub assembly drawingc) Detail Drawingd) Part Drawinge) Production Drawingf) Machine Drawing

8. List out different type of lines used in drafting

CATIA Basics

Working With A Session: 1. A Session is defined by a set of models and a SESSION MANAGER.2. The SESSION MANAGER configures a CATIA session and manages

the data accessed by the user.3. Working with a session is working in context; this allows you to visualize

your digital mock-up and to perform various simulations.4. A session is stored in a SESSION-type file. It must be considered as a

temporary work environment save.5. No data transfer capability is provided on a session.

Hints & Tips:1. When a model has been once active, you can see a (emptyset symbol) or () at the end of the model name in the Window Menu Bar.

2 Displaying the working plane parallel to the screen on workstation: Select view+current 2D plane or key in p to work in the current 2D plane

3 Warning about Circles: Circles are created in CATIA with a break point

located at the 3 O’clock position. i.e while creating limit points on circle, one centre point and another point at 3 O’clock position will be created.

4 Methodology-Visualizing different thickness: If we cannot visualize the different thickness on the screen, display the local Transformation window with the STD option and set the thickness

option to ON.

5 Forcing colours: During the design phase, we may want to highlight an area of our part. The colour forcing option allows us to force the same colour onto the elements.

6. About the Colour Palette: Activate the local transformation window(PF4 key or Mouse buttons 1 and 3) select COL option. The colour palette has two zones:The first six boxes manage the colour of the CATIA graphics screen.The others manage the palette of available colours in model

7. Creating Standard Model: To avoid having to customize model standards each Time while creating a new part, we can create a standard model for which we set the standards we need before saving it for subsequent use. Then each time when we need a new model, we read the standard model instead of creating a new one.

8. Selection: while selecting a contour or profile, we can use *SEQ or *PRF instead Of selecting all the contours or pressing Autosearch.

9. Applying Filters: The filter we apply is supposed to let us see the geometry only, but we can see the axis system even though it is on layer 0. The current layer is always displayed. If we create geometry, we create it in the current layer. We have to be able to see the elements we are creating. To be sure to display only the geometry we want, ensure that the current layer is an empty layer.

DITTO: An image (or occurance) of the geometric elements of a detail which

is transferred into another workspace is called ditto.A ditto can be used as a single element, but its constituent geometric

elements can be used for further creations in the receiving workspace.If the geometric elements of the initial detail are modified, all the

dittos are automatically updatedThe ditto mode is useful:1. To keep a subset independent from the rest of the model2. To place several identical subsets in the model, while creating them only

once in the model (memory space saving)3. To allow easy modification of a repetitive subset. Such a modification is

applied to each occurrence of the modelApplns.: Mainly used in designing 1) Piping and 2) Tubing

1. What is the abbreviation for CATIA?

2. What is the extension for a CATIA file system?

3. What is the operating system on which CATIA work?

4. CATIA can be used for a) only 3D modelingb) only 3D modeling and analysis.c) 3D modeling analysis, simulation and integrated appliationd) none of the above.

5. What is the difference between crv and ccv.

6. What is meant by wire frame modeling.

7. What are Boolian operators? Name a four boolian operators.

8. How CATIA is divided in to?

9. What is a 2D profile?

10.What is the difference between models and files in CATIA.

11.How do you activate the alphanumeric window in CATIA.

12.What is a primitive ? what are the basic type?

13.What is a surface element?

14.What is the difference between surface modeling and solid modeling.

15.Give the expansion for the following.#IGES#STEP#STL#DXF

16.Difference between surfaces,faces and skin?

17.What is meant by volume element?

18.What are the two working modes in CATIA?

19.Name the basic features which are mostly used in CATIA solid modeling?

20.What is CSG tree and give its expansion?

21.A node in a CSG tree represents___________22.A terminal branch in a CSG tree represents_____________23.How to access CSG tree?

24.What does LPFK stands for ? Explain briefly?

25.Give the expansion for :-#NHR#HLR#SHD modes

26.What is the max number of layers in CATIA? Which is the default first layer.

27.What are NURBS? Give its expansion?

28.What are the things to be considered before starting a 3D modeling work?

29.What is the hierarchy of making a complex solid design?

30.Give the multi select option for a face, surface, volume and skin.

31.What is a master workspaces? How do you create aditional workspaces?

32.____________ switch is used to change the current workspaces?33.Differentiate between dittos and details.

34.What is functional surface?

35.Intersection of two functional surfaces are called____________36.Differentiate between neutral and parting element in a draft.

37.Differentiate between cliff and rolling edge?

38.What is Dynamic sketcher? Where is it used?

39.Use of compass in DS.

40.Sketcher colours convey a different meaning than the same colours in CATIA,name the color and explain.

41.Type of dim constraints available in DS?

42.What is the difference between connect and corner under surf1 function?

43.What is planer face? How does it differ from face created from surace?

44.How does surf2 function differ from surf1 function?

45.How does surface element represented in CATIA?

46.What is constraint element in CATIA?

47.What is spline element?

48.Can you isolate a parameterized geometry in CATIA?

49.How will you break a parameterized relationship in CATIA?

50.What is meant bye local parameterization?

51.Explain briefly about the command paramlink?

52.Parameterizing a geomentric element consists of#Evaluating its cahrectristics#Adding relationships.#Modifying the dimensions.#Both(ii)&(iii)#Both (I)&(ii)

53.What is the purpose of feature based design?

54.Explain briefly about the commands used in FBD?

55.Explain briefly about the various start functions in CATIA?

56.What is local function window? Explain briefly.

57.What are the constraints available in assembly modeling ?

58.How is the window divided in assembly?

59.What are the contextual commands available on constraints?

60.What are the contextual commands available on parts?

61.What is the extension for the assembly file ?

62.Constraints in assy is highlighted in 3 color. explain.

63.What are the parameters that can be defined by a law?

64.What are the different curves required to define a radius law?

65.What are the 4 principal stds available in CATIA for dim

66.Diff. Between CLIP & BREAKOUT in auxview2.

67.What is the use of LOCK in drafting?

68.Difference between TEXT & TEXTD2 (OR) AUXVIEW & ALIXVIEW?

69.Use PACK in ERASE command.

CATIA QUESTIONS AND ANSWERS

1. What is CATIA? What are the different modules of CATIA? What are the main Features of CATIA?

CATIA: Computer Aided Three Dimensional Interactive Application It is used to create three-dimensional geometric models using wireframe, surface, and solid modeling constructions.

Additional application modules incorporated with CATIA provide capabilities for: Kinematics Robotics FEM mesh generation FEM solutions NC Mill NC Lathe Programming Piping Design Structural Member Design and Image Generation

Additional Modules allow data exchange between CATIA and other applications and provide an interface to the internal CATIA mathematical routines and user interface.

Main Features of CATIA are: Maintains a full three-dimensional data base Allows direct construction of 3D Wireframe and Solid

Models 3D space elements & 2D draw elements can co-exist

simultaneously in the same model Automatic generation of machining instructions to drive an

NC tool Geometry interface which can accept geometry from other

systems and analysis programs as well as extract data for delivery to other systems

Kinematic module which simulates the movement of part is space

Robotics module to simulate a robots workenvelope

2. What are the relations between SURFACE, FACE, SKIN and VOLUME?

SURFACE: A Surface is an infinitely thin, mathematically defined contoured

area in space. It is displayed visually by isoparametric curves and boundary curves.

In simple terms a surface is an entity that has length and width, but essentially no thickness.

In CATIA Surface is a Parent element for Face and Skin.

FACE: It is a portion on a surface defined with curves as boundaries or it

is a portion in a plane defined with curves or lines as boundaries Face is a child of Surface.

SKIN: A Skin is a set of joined faces, surfaces, skins, or volumes, similar

to the volume, but with a single domain and without closure condition.

In addition, an offset can be associated with each of the faces. Since Skin is derived either from surfaces or faces, hence it is also

a child of face or surface.

VOLUME: A Volume is a set of joined faces or surfaces or skins or volume,

with total closed domains. While creating Volume the order of selecting the faces is

important. Also a Volume can have an inner domain.

3. What is the difference between SOLIDE and SOLIDM?

SL NO.

SOLID EXACT SOLID MOCK-UP

1 Exact Solids manipulates an exact type, that is, a non-approximated Boundary Representation

Mock-up Solids manipulates an approximated type B-Rep, that is, a representation resulting from an approximation of the non-planar forms by planar facets

2. They are distinguished by having precisely defined surface definitions.

They incorporate surfaces that are approximated using discrete planar facets

3 They can be used for all other CATIA operations including NC programming

They can be used effectively for object visualization, constructing mockups to validate assembly operations or for kinematic, dynamic and FEM analysis

4. These models have applications in more artistic situations with highly contoured surfacesNote: All curves are displayed as polylines with decretization being determined to achieve the most realistic appearance without excessive computational effort

These models are simple but are of little value for applications requiring precise surface definition

4. What is the difference between PRIMITIVE and FEATURE?PRIMITIVE: It is generally the simplest solid element that can be create.The three types of primitives are:

a) Canonical Primitives--- 1) Defined by geometric values: ---Parallelepiped

---Cylinder---Cone---Sphere---Torus

2) Defined by a contour and geometric values : ---Revolution: element obtained by rotating an open or closed

profile about an axis---Sweep: element obtained by sliding a

contour along a spine while the normal to the contour plane remains parallel to the tangent to the spine

a) Complex Primitives--- These are SOL type elements obtained:

* from VOL type elements * from Skin surfaces or non-planar faces by -- closing through offsetting the same

surface -- closing through projection onto a

plane -- closing using planar faces

b) Macro Primitives --- Macroprimitives are SOL type elements

obtained from dittos (DIT type elements). The corresponding detail has SOL type elements itself.

FEATURE: 1. A Feature is a set of user defined technological object

consisting of: a geometry a Parametric definition and technological attributes

2. Normally, features are characteristic details of a part that have a strong correspondence or linkage to a particular manufacturing process

(Ex: a counterbored hole, a boss around a hole, a pocket)3. Features are defined by the user or the administrator, stored in

the library and used to create parts of features, compound features

5. What is the difference between the SOLIDE+MODIFY+OPERATION+DUPLICATE and TRANSFORM+SYMMETRY?

The first difference between these two operations is that with the SOLIDE+modify+operation, you must first indicate whether or not this is

going to be a duplication or replacement. The second major difference between Transform and Modify+operation+duplicat is that Transform keeps a link between the originating primitive where mod-op-dup does not. In other words, with Transform, if a change is made to the originating solid, the copied solids will also change.

6. What is the difference between SURF1+GEOEXTR and LIMIT2+SURFACE+EXTRAPOLATE?

SURF1+GEOEXTR LIMIT2+SURFACE+EXTRAPOLATE

Extrapolated surface will not be having the same deviation and degree of the original surface but is tangent only to the one side of the surface.(i.e, straight segment surface)

Extrapolated surface will be having the same shape, deviation and degree of original surface.

Surface generated through extrapolation is separate entity with original surface and needs concatenation of surfaces.

The resultant surface after extrapolation is single surface.(i.e automatically concatenated)

9 What is the use of Part Editor Window?Part editor allows visualization and real time modification of your

designed part by selecting or directly acting on the feature structure of the part.

10 What are contextual menu and its applications?Clicking on a branch or feature displays the corresponding contextual

menu. This tool help you get commonly used operations faster such as:

* Rename: to rename the solid* Reorder: to move the element within the structure of the solid* Color: to change the colour of the solid* Parent: to manage the parents of the element* Delete: to delete the element (=delete no keep)* Break: to separate one branch from the whole solid (=delete keep)* Active/Inactive: to activate or inactivate the element (or only fillets or drafts of the branch)* Collapse/Expand: to reduce a whole branch to a single component (or vice versa) Such as a group of holes* Smart/Unsmart: to activate or deactivate smart solid

Also in part editor, their two types of features lists can be possible.1. Simplified view of feature list:

2. Detailed view of feature list: --- internal views of feature branches and macroprimitves are displayed

9 What is Model? A Model is an individual drawing, read into main memory for interactive processing.

Models can contain one or more workspaces which inturn can contain one or more sets with zero or more elements in each.

10 What are the functions of FORMTOOL? Formtool allows performing semiautomatic filleting, trimming and

breaking operations on a shape with sharp edges. Formtool creates surfaces, face and skin in a single interaction Skins are the main tool of the Formtool function since they allow

us to combine faces and consider them as a single entity. Formtool allows creating variable radius fillet.

11 What is the use of LAW function and where is its application?The purposes of a law are easy to understand, but its application may

be more complex. Laws involve the creation of geometry to control differing aspects of a surface. A surface may be controlled by aspects of area, radius (width) or angle. Depending on the transitions that need to made to another surfacic element, users may need to develop 2 dimensional wireframe that will dictate how the transition is to be made in ratio proportion to the application of the law geometry. It sounds a lot harder than it is to use.

12 What is a set?A set is a disjoint group of elements of different types that can be

processed together.

13 What is an element?Elements are the lowest level geometry entity created by their

corresponding functions.

14 What is a Session?Session is a set of models. Sessions are used to allow two or more models to be positioned to

create a more complex assembly. A Session can contain several ‘Passive’ Models but only a single

‘Active’ Model, which is the model displayed in the CATIA workspace.A Session is defined by a set of models and a SESSION MANAGER.

The SESSION MANAGER configures a CATIA session and manages the data accessed by the user.

Working with a session is working in context; this allows you to visualize your digital mock-up and to perform various simulations.

A session is stored in a SESSION-type file. It must be considered as a temporary work environment save.

No data transfer capability is provided on a session.15 What is Workspace? What is the difference between Master and Detail

Workspace?Each Model can have one *MASTER workspace which is the area in

which the model is created and manipulated. In addition, a model can have zero or more workspaces called

DETAIL workspaces. These are auxiliary workspaces that contain elements that are to be duplicated to several locations in the *MASTER workspace.

In addition, DETAIL workspace can also be organized into separate library files using the LIBRARY Function. These can be shared with many models to allow organizational standardization

17 Is it necessary to break cylindrical surface along vertically for generation of faces?

No need to brake the surface because the catia itself automatically create two

faces along circumference

19 What is the difference between SPACE mode and DRAW mode?SPACE MODE:a. In Space Mode, it is possible but often quite awkward to work directly

in the 3D Space. Ex: Entering points that lie in a plane can be tedious when three co-ordinates must be entered for each point.

b. In Space Mode, CATIA allows the user to temporarily switch into a 2D mode to create, view or manipulate elements.

c. The 2D Mode is very convenient for working with 3D Geometry in the Space Mode of operation.

DRAW MODE:a. The Draw Mode of operation is purely 2D Mode in which CATIA can

be usedfor the drafting purposes.

b. The geometry is 2D only but can be organized into up to 255 views. Each view can be defined by a geometric transformation with respect to another view. In this way, it is possible to create a multiview orthographic projection engineering drawing.

c. The Draw Mode can be used independently or it can be used to project a full 3D Model into Multiple Orthographic projections for purpose of preparing a traditional engineering drawing. This process is referred to as CATIA Draw/Space Integration and is managed by special CATIA functions.

d. The Draw Mode is probably the most useful way to generate paper copies of a CATIA Model for engineering purposes.

20 Write the difference between a. DITTO,COPY and TRANSFER options in DETAIL functionb. Helical Pitch and Radial Pitch in SURF1+REVOLUN+UNSPECc. PT type element and CST type elementd. ARC and SPLINEe. CURV1+COMBINE and CURV1+PROJECT

21 Whether the Curves have orientation or not?22 Whether segment lines can be made into unlimited lines?23 How many types of transformations can be achieved in CATIA?24 Describe any two types of surface modifications?25 What is the difference between the Bezier spline and Bezier Curve?

Which one will be the best to use and why?26 What is the Major differences between SURF2 surface, Net Surface and

NURBS Surface? Where and when these surfaces have applications?27 Explain the design procedure of the Free Form Design with example?28 How do you check the accuracy of the surface?29 How to access the Parent Element of the model using Contextual Menu

of the Part Editor Window?30 What are the different modeling methods available on CATIA? Which

one you choose the best method?

Infosys Questions.31 What is harness?32 Which one you would feel compatible between solid model and surface

model?33 If we give you various section contours of different size with 10mm

intervals, How you are going to generate a surface model using this data?34 What is the difference between surf1 and surf2?35 How do you generate surface model of stiffener or doubler using NMG?

CATIA Version 5Platform P1 and Platform P2

Multiple sets of solutions for each user profiles. The two platforms, P1 and P2, are built on the common V5 architecture, giving customers full

flexibility to grow their installations. Products from CATIA P1 are fully operational on a CATIA P2 platform.

P1 Platform:CATIA P1 provides core modeling for small and mid size process-

centric customers wanting to extend their design capabilities to embrace digital product definition and to position themselves for e-business. The P1 Platform has a pure Windows look and feel giving unmatched ease of learning and ease of use

P1 Platform is also an excellent solution for existing customers who can address many supporting areas of their business making CATIA capability accessible to people that previously could not justify 3D modeling because of the hardware or training overhead.

CATIA P1 integrates growth capacity for customer methodologies, from interactive 2D drafting to full digital product development processes. All products available on Platform P1 are fully operational on a P2 Platform.

The P1 platform is available on Windows 95, 98, NT and UNIX, and includes the following product portfolio:

a) Mechanical Design Solutions:1. CATIA Part Design 12. CATIA Assembly Design 13. CATIA Wireframe and Surface 14. CATIA Sheetmetal Design 15. CATIA Generative Drafting 1 6. CATIA Interactive Drafting 17. CADAM Drafting for V5 

b) Analysis Solutions:1. CATIA Generative Part Structural Analysis 1 

c) Product Synthesis Solutions:1. CATIA DMU Navigator 12. CATIA DMU Space Analysis 1 

d) Infrastructure Solutions:1. CATIA Team PDM 12. CATIA IGES Interfaces 3. CATIA CADAM Interface 14. CATIA STEP AP203 Interface 15. CATIA Real time Rendering 1 

6. CATIA Object Manager 1

P2 Platform:CATIA P2 provides a unique environment for process-centric

customers to create their digital enterprise by modeling their products, processes and resources, thus supporting their end-to-end product lifecycle from concept to product in operation.

P2 Platform provides an extended set of solutions based on knowledge engineering and hybrid modeling technology. It allows to drive both Form and Fit through Function specification as part of the integrated digital mock-up.

P2 Platform enables knowledge driven design that captures and reuses a company’s intellectual capital to support engineering intuition, creativity and innovation while allowing engineers to rapidly iterate error-free design alternatives.

P2 Platform provides for an innovative "3D Windows" user interface that delivers increased productivity and is fun to use.

The P2 platform is available on Windows NT and UNIX and includes the following product portfolio:

a) Mechanical Design Solutions:1. CATIA Part Design 22. CATIA Assembly Design 23. CATIA Wireframe and Surface 24. CATIA Sheetmetal Design 25. CATIA Generative Drafting 2 6. CATIA Interactive Drafting 17. CADAM Drafting for V5

b) Shape Design & Styling Solutions:1. CATIA FreeStyle Shaper 22. CATIA FreeStyle Optimizer 23. CATIA Generative Shape Design 2

c) Analysis Solutions:1. CATIA Generative Part Structural Analysis 22. CATIA Generative Assembly Structural Analysis 2

d) Equipment & Systems Engineering Solutions:1. CATIA System Routing 22. CATIA Circuit Board Design 2

e) Product Synthesis Solutions:1. CATIA DMU Optimizer 22. CATIA DMU Space Analysis 23. CATIA DMU Fitting Simulator 24. CATIA DMU Kinematics Simulator 25. CATIA DMU Navigator 2

f) Infrastructure Solutions:1. CATIA Knowledge Advisor 22. CATIA Knowledge Expert 23. CATIA Generative Knowledge 24. CATIA Team PDM 15. CATIA Version 4 Integration 26. CATIA IGES Interfaces 17. CATIA CADAM Interface 18. CATIA STEP AP203 Interface 19. CATIA Real time Rendering 110.CATIA Object Manager 2

g) Plant Solutions: 1. CATIA Plant Layout 2