3D CAD Techniques

• Advanced Higher Graphic Communication offers a revision pack with solutions from Kinross High School.

3D CAD Techniques

• Morphing: Envisions a 3D model surrounded by a mesh, able to be manipulated by pulling, stretching, or scaling, and aids in effective manufacturing by smoothing designs or adding strength.
• Extrusion along a path (sweeps): A 3D command that enables a profile to follow a path, generating surfaces where a curve is created, which is useful in creating bodywork for vehicles by following one or two paths.
• Regular and irregular fillets and chamfers: Smooth edges via curves (fillets) or 45° cuts (chamfers); useful when intersecting objects need tapering or size/angle adjustments.
• Lofting/Blending: Creates surfaces or solids between two+ profiles/curves on different planes, which is useful for transition pieces like toilets or ducting.
• Solid Modeling: Solid models are created by drawing 2D shapes and using a 3D feature (extrude, loft) to create various 3D forms which can then be edited from a starting point of a closed shape.
• Surface Modelling: Begins with an entity (a line) that can be extruded or revolved with thickness to create a surface, or create a "Skin" between 2D or 3D curves, allowing for smooth or crisp intersections, which is more freeform than solid modeling and can be geometrically incorrect, unlike solid models that must be geometrically correct.

CAD Illustration and Lighting Techniques

• Texture mapping: Applies 2D patterns/textures to a 3D object allowing the software to distort the pattern for realistic application, enhancing CAD model realism and designer visualization of the finished product.
• Bump-mapping: Texture application specific to a surface to create light/shadow effects for complex scenes in gaming and architectural industries which includes adjusting brightness levels.
• Reflection (lighting technique): Light retraces back into the same medium for realistic rendered images, that depends on the surface, whether it is shiny metal or darker dull wood.
• Specularity: Determines a surface's reflectiveness, where adjusting specular highlights can create glossy or blurry reflections depending on surface roughness.
• Ambience (ambient lighting): Provides constant illumination to a 3D environment without a specific source or direction, creating a simple form of lighting, which is mainly used to provide an environment with a simple form of lighting.
• Depth-of-field (DOF): Distance between the nearest and farthest objects within an image. It is a visualization aid to improve understanding of relationships between objects in 3D projection or complex data sets.
• Image Based Lighting/High Dynamic Range Imagery (IBL/HDRI): Illuminates objects/scenes with real-world objects by applying an HDR image to a virtual sphere, especially useful for objects appearing in real environments using the HDR image.
• Volumetrics: Renders 3D space data for scientific/medical professions and smoke rendering in games via rendering objects based on their complete structure, not just the surface.

CAD Techniques in Production of 3D Graphics

• Polygons, sometimes triangular in shape, are used in computer graphics to form 3D images faster which allows you place texture mapping which leads to more realistic rendering for animation.
• Add - Combines the total volume of two or more solids/regions into one composite object.
• Subtract - Removes one volume of two solids/regions from another.
• Intersect - Creates a composite solid from the common volume of overlapping solids by removing non-overlapping portions.
• Slice - Clips a solid model along a work plane in modelling mode using the sketch plane to show a sectional view of parts that are normally hidden as you utilise project geometry mode for specific parts.

Simulation Methods: FEA and CFD

• Finite Element Analysis (FEA): Digital testing of products used on mechanical components, also known as Digital Prototyping to digitally design, test, optimize, validate, and visualize products throughout development.
• FEA creates innovative digital prototypes via CAD to meet design objectives (output, efficiency, speed, cost), reducing development and time-to-market.
• FEA can show assessments the product can perform with moving parts, to determine product failure, and see product components interactions.
• Computes areas of a structure and determines strength/weakness, adding it together for overall component assessment.
• FEA reduces the need for numerous physical prototypes by digitally testing using Digital Prototyping.
• FEA can catch design problems early, reducing downstream changes by simulating in early stages to avoid failures during testing or manufacturing.
• Computational Fluid Dynamics (CFD): Digitally tests airflow through a building internals for cost-effective improvements to internal/external design by establishing how airflow affects occupants and enabling informed decisions on furniture placement, heating systems, and ceiling height.
• CFD uses complex mathematical formulas to analyze and establish volume and flow rates through confined areas, as well as provides instantaneous volume data for design, facilitating new building designs, heat/control, and environmental efficiency.

CAD/CAM Methods and Techniques

• 3D Model Manipulation for CAM Production: Production engineers use CAD models/drawings with strict protocols to ensure data is consistent across layers.
• For CNC lathe shafts, a half profile is required with all sizes drawn to mid tolerance to produce tool paths, for clean 3D CAD shapes that are required without additional features.
• Design model is used to produce a CNC program for reproduction which ensures the finished part matches required size by manufacturing original models to mid tolerance.
• Communicating Surface Finish and Datums: Tolerance between features must remain within prescribed limits for working drawings, which means you must add datum features, control boxes, and surface finish symbols along with original dimensions.
• Datum features like concentricity, parallel, flatness, and perpendicularity are added to dimensioned surface which is why tolerance is connected to that face.
• Gathering Model Information for manufacturing: Establishes total mass for irregular shapes (material-dependent) and centre of gravity to help facilitate lifting and weight distribution.

CAD/CAM File Formats

• Standard Tessellation Language/stereo lithography file format (STL): A widely supported file format for rapid prototyping, 3D printing, and computer-aided manufacturing that describes only a three-dimensional object's surface geometry without color or texture information.
• The STL file is a standard file type used by most additive manufacturing systems consisting of a triangulated representation of a 3D CAD model with faceting, where parameters affect level of faceting.
• The degree of detail in a STL file impacts file size and processing time, so you can expect a larger file size that takes up more time to process.
• Direct Exchange Format (DXF): CAD vector image file used for 2D drawings, the DXF file format is similar to DWG but ASCII based for better compatibility with computer applications.
• The Direct Exchange Format is used for 2D manufacturing like plasma and laser cutting.
• Drawing Format (DWG): Native file format for AutoCAD data files, including designs, geometric data, text, maps, and photos, that signifies compatibility within the AutoCAD technology.
• Virtual Reality Modelling Language (VRML): Used for describing three-dimensional (3-D) image sequences that allows user interactions to build sequences of visual images into Web settings and is intended for a user to interact with.
• 3D Studio (3DS) files: A file format used by 3D modeling, animation and rendering software and that provides an import/export format, retaining only essential geometry, texture and lighting data.

Desktop Publishing

• Desktop publishing can improve page layout for effective design that companies can employ, create an effective design, allows documents to be customized, common templates reduce production time/cost, layouts use functions for accuracy, editing tools/images facilitate quick changes, and minimizes document design/publishing time.
• DTP Benefits for Fast-Food Company- Digital control minimizes waste, and modern printing uses 100% recycled paper.
• DTP Benefits for Sportswear Company expanding to web-site, electronic news reduces paper use, text/graphics are imported remotely, files sent via email, communication is streamlined, websites are globally accessible and multilingual.

Desktop Publishing: File Types

• JPEG (Joint Photographic Experts Group): It is a raster image file, a commonly used data compressed method where optimization provides balance between file size/quality; used in digital cameras, mobile devices and websites.

• PNG (Portable Network Graphic): It is a raster image file that supports transparency and is high quality in comparison to JPG but unsuitable for professional prints; used in web with transparent backgrounds or as logos/overlay images.

• BMP (Bitmap Image File): It is a raser image file and stores color data with no compression causing high quality graphics but with large file sizes; used with hard copy print outs.

• PDF (Portable Document Format): Cross-platform file format works on every computer that supports flattened fonts/graphics reducing file size which means it is useful in document sharing that doesn't need specific hardware or OS.

• AI (Adobe Illustrator File): Vector graphic by Adobe that uses algorithms to provide high quality images and is suitable in large/small scales and used for logos/illustrations/graphics and general prints.

• WMV (Windows Media Video): Video file by Microsoft for optimum storage that is useful across internet video streaming.

• AVI (Audio Video Interleave): Video file by Microsoft that allows playback using a multitude of types and also includes subtitles.

• 3GP (3rd Generation Partnership Project): Mobile Multimedia between 3G phone.

• Quicktime file formats: Apple file that can use video/pictures/sound.

Types of Printing Jobs

• Laser printing- Toner is dry as opposed to inkjet which is wet which means the ink does not smear.
• Personal laser printers average 200 pages per week; workgroup printers hit 1000 pages, and production printers can exceed 50,000 pages with costly production runs.
• Most have standard paper sizes, where high end printers use continuous sheets and all are capable of transparency, labels, and lightweight cards.
• Standard resolution is 600 dpi, high end is 2400 with the ability to correct with Resolution Enhancement Technology without enhancing the resolution.
• Personal printers typically reach 8 ppm while a workgroup can stretch to 24ppm and 700 pages by production printers.
• Ink Jet Printers - Inexpensive lightweight and is useful on personal computers but copies need time to dry.
• Most inkjet printers don't lend themselves to to volume jobs.
• Require use of non-porous paper.
• Average resolution reach resolution of at least 300 dpi and some can reach 600.
• Are slow compared to others.
• Wide-format Printing - Inkjet typically produces colors by using CMYK and means the technology does not need replacement plates since it uses digital printing.
• More economical as opposed to techniques like screen printing, depends on the kind of print run.
• Applies to paper, vinyl, banner type.
• High Quality.
• Slow but smaller print runs or 1 off banners will be very small.
• Screen printing - Simplest version is making a stencil that can attach on nylong to a mesh fame, excellent printing of color with vibrant on specialty products.
• Economical due to its cheap set up as increase of speeds will increase.
• Able to print all kinds of materials, including clothing/metal.
• Adaptibility allows the screens used to be used again, with ability to have vibrant light colors used.
• Ranges from 4000 to 6000, using the modern quick process that saves time.
• Offset lithography - Very popular technique can be used on most matter that is printed.
• Cost effective to doing so and is used for high volumes.
• Typically used for newspapers/brochures/advertisment.
• Has a wide range reproduction that allows for metallic colors and accurate colors.
• Fastest speed.
• Solid Ink Systems - Using ink sticks instead of liquid as a safe way to save waste by using colors via printers.
• Attracts businesses by offering good quality that can print up using 40 printing as it heats.
• Used with paper.
• Can be placed well to get the colors.
• Advantage ink printers, they help prevent oxygen.

Colour Systems

• RGB (Red, Green, Blue): An additive color model which means red, green, and blue light are added together in various ways to reproduce colors; used in sensing, representation, and display of images across electronic systems as well as video or image capturing.
• Each pixel on the product screen has 3 small sections which are arranged in a rectangular screen to trick it into generating the color.
• CMYK (Cyan, Yellow, Magenta, and Black): A substractive which is the most popular printing models that is used in colors.
• Colors are known as separation and may consist of Cyan Blue and black where black ink helps give the definition as the three color together give a muddier tone.
• Pantone: The Pantone Matching System (PMS) uses a color space in printing which helps manufacture and is standard language.

Printing Terms

• Edge-to-Edge Printing: Also called a full bleed, this is when to paper will crop the image which extends pass its bounds with modern printer but with modern printers you should be able to.
• Bleed: Printing outside the edges.
• Gutter Vertical space between the columns.
• Registration marks: With off set printing used to help.
• Colour calibaration: Match screen printer.
• Points per line: Clearer image.
• Photo reduction: Less loss quality.
• Camera-ready copy: Pre-printing.
• Dupelxing: A sheet of paper.
• Paper wait: Gsm.
• Paper capacity: How much can be seen.
• Use of calendaring: Get it to be flat.

Aspects of Digital Anmination

• Motion-capture: Live events and translating accurate but is expensive on it and takes its time while the latest.
• Stop-frame animation:: Cinematic approach. is normally but labor takes is time.
• Motion tweening: This will be displayed move a short period. It is a effective type.