Technical Illustrations with NX CAD NPR support

GEA Farm Technologies
Alternative process approach and hints for NPR
Matthias Ahrens – Technical Solutions Manager
100164 BU Dairy & Farm Equipment – BU Support
2015-01-14
Technical Illustrations with NX CAD support

GEA Farm Technologies2 2015-01-14 / Technical Illustrations with NX CAD support / M. Ahrens
• Review of process alternative to generate raw images for non-
photorealistic product illustrations by the 3D CAD model source
directly.
• Provide tips, tricks and hints for setups in SIEMENS PLM’s NX CAD
to get adequate source images.
• Provide hints about tools and applications, which can be utilized for
post – processing, composing and final illustration…
Intent

• For describing specific sub modules and functions in IO manuals and
other technical papers and brochures a “Non – Photorealistic –
Rendering” resp. illustration is often much more feasible in
comparison to a product photo by the fact that it can be customized to
focus the audience to a dedicated area of interest!
Why NP(R) Illustrations?
Source: http://technicalillustrators.org Source: LIEBHERR Crane Manual Source: Melktechnik Lauterbach

The 3D CAD Model as source for illustrations
3D CAD Engineer
Project Manager Product Manager Purchasing / Supplier
Numerical SimulationTeam - Collaboration
Assembly InstructionsInternal Visualization (e.g. SAP)
Sales / Service Tools
Work Officer
CAM / CNC
Technical Illustrations
Technical Service
Marketing
External StudioWeb Presenting (e.g. 360°)
Embrace of
3D Model
utilization

• Modern 3D CAD tools are offering a quick path to generate isometric
drawing views of technical products, which can be used as first shot
resp. for internal documentation only!
• By absence of a few important visual effect, those images are often
not sufficient to be used in Operating Manuals, etc.
2D CAD drawing as Technical Illustration?

• The most important part in a technical illustration is the utilization of
shadows to provide a visual information of depth and a logical order!
• A technical drawing is sticking into details while a technical illustration
should focus on specific topics or components only
(e.g. by Emphasis).
• …
Differences: Drawing vs. Illustration?
Technical Drawing Technical Illustration

CAD -> Illustration: Process A
3D CAD
•Design the model
•Export the model as neutral file format
3D / 2D
Illustration
•Import the 3D model
•Colorize and prepare basic annotation
•Prepare perspective views
•Render 2D NPR images
•Export 2D raster or vector images
2D Illustration
•Import 2D raster image or vector image
•Finalize illustration
•Export final illustration
DTP / CMS
•Import illustration into documentation system
•Include illustration in document
• It requires often additional
investments into specialist
3D->2D illustration tools!
Source: PTC

CAD -> Illustration: Process B
3D CAD
•Design the model
•Colorize
•Prepare perspective views
•Render 2D NPR images (e.g. multi pass)
•Export 2D raster images
2D image
manipulation
•Import 2D raster images
•Cleanup or compose
•Export enhanced images
2D Illustration
•Import 2D raster image and maybe vector trace
•Finalize illustration
•Export final illustration
DTP / CMS
•Import illustration into documentation system
•Include illustration in document
• Utilize NPR methods inside the
CAD package, if available.
• The image composing is done
outside on 2D images only!
• Sometimes faster update cycles
in case of design iterations on
the original source model
• Less investment in specialized
tools

Process B: NX – License - GUI Setup
• At least the NX MACH 2 Product Design license bundle is required!
• It is not required to activate “Ray Traced Studio” or enter the
“Advanced Studio” to setup the scene and required parameters!
• The most important dialogs can be accessed via the menu path or the
related icons, which can be added to the GUI on demand
Source: SIEMENS PLM – NX Mach Series Design Solutions

Process B: NX – view / camera capabilities
• In NX CAD take care for “Model Views” and “Cameras”, which should
correspond and should be managed in combination!
• A “Model View” handles basic information like “visible components”,
cutouts, etc. while the “Camera” offers advanced optical adjustments
like lense settings, etc.
• Define a fixed “Camera” for each illustration!

Process B: Axonometric projection, etc.!
• Isometric, Dimetric and Trimetric perspectives are often used in
classical illustrations to visualize 3D objects!
• In modern business setups the requirement to get real dimensions by
“measuring” within the axonometric view is no longer valid. Therefore
I propose to use “real perspective” views in the illustration instead!
Source: Hamiltonian Of Design
NX Trimetric View NX „Real Perspective“ View

Process B: Artistic Image NPR Rendering in NX
• In addition to the photorealistic functions of the embedded Lightworks
Design Ltd. render engine, you can utilize a few options of their sketch
render resp. NPR pipeline in NX CAD (Artistic Image).
Source: GOOGLE - Lightworks Author 9.1 – Sketch rendering Guide (Lightworks Design Ltd.)

Process B: The Image Quality - Contour
• The “High Quality Image” settings are offering options, which are
honored by the “Sketch” render too.
• E.g. the “Facets” control has significant impact to the smoothness of
the contour rendering!

Process B: The Image Quality – Size / Resolution
• Check out upfront the size and the resolution of the image, you want
to get at the final end and if the result will be used on the web or in
print media!
• Larger values are often better and can be down sampled later on!
• But carefully check out what your post-
processing tools can handle!
(e.g. Vector – Trace engine)!
• A quadratic image is better for
multi layer positioning!
Calculation Example:
Paper Size: A4
Metric: 210 x 297 mm
with
25.4 mm per inch
results into
8.27 x 11.69 in
with
300 DPI (Dots Per Inch)
results into matrix of
2481 x 3507 pixels
as minimum size
E.g. CorelDRAW’s PowerTRACE warning on
handling very large input raster images

Process B: The Background
• Take care that you set the “Background” for the rendering process to
pure – plain white via the “Scene Editor“ dialog!
• Keep in mind that the “High Quality Image” and “Artistic Image” render
pipelines are not “WYSIWYG” processes!

Process B: The Lights and Shadows for NPR
• Instead of HDRI Imaged
Based Lighting the
“classical” light setup is
better to define NPR
shadow accurately!
• Take also care for
“Intensity” and “Shadow”
activation!
• The “Studio” mode can be
used to review quickly the
shadow layer!
• Recommendation:
“Less is often more!”
Sometime a simple frontal
Light source is enough!

Process B: Multiple NPR’s required
• To keep the flexibility on the “Post Processing” resp. “Composing”
step a kind of “Multi pass” Rendering can be performed with the same
High – Quality – Image settings and the same Camera!
• Use the dedicated buttons in the Artistic Image dialog to render and
erase NPR’s.
• If a usefully NPR is rendered open the High Quality Image dialog
directly and use the “Save” option!
• In the dialog you can setup JPEG as output format by simply editing
the file extension to .jpg!

Process B: First Shot – Raster Composing
• These individual passes can be merged in standard raster image
manipulation tools like Adobe PHOTOSHOP, Corel PHOTO-PAINT or
GIMP (Open Source), etc. as separate layers or objects!
• The opacity and tone setting can be control there much easier!
Colors
Lines
Shadows

Process B: Layer opacity setting in GIMP
• Inside GIMP use “Colors” -> “Color to Alpha…” or the “Fuzzy Select
Tool” and make the white areas around the objects, lines transparent!
• You can also utilize other image tunings like color saturation, etc.?

Process B: NX NPR Pass 1: Colors
• Use the “Cartoon” style to generate a
colorized image!
• Maybe take care for reducing the
Outline Width and the outline color!
• Reduce “Shadow” effects to minimum
by turning off related lights and
“brighten” the entire scene!

Process B: NX NPR Pass 2: Lines
• Use the “Lines and Shadows” style with
“white” shadows to generate a line wire
image, which fits exact over the others
in positions and camera lens settings!
• Maybe “play” with the Outline Width
according to the image utilization!

Process B: NX NPR Pass 3: Shadows
• Run the same “Lines and Shadows”
style a second time with “white”
outlines and black “shadows”!
• Take care that shadows are processed
by the relevant light settings!
• The tone of the shadow layer can be
managed later on in the composing by
the opacity level!

Process B: Vector Trace
• Especially if the intent is to create full vector illustrations the “Multi
pass” rendering process can produce better sources for the different
trace tools! E.g. INKSCAPE’s POTRACE engine (Open Source)!
NX Raster Image
Lines
GIMP
Vectors after
Trace Bitmap

• A few tools are offering dedicated Outline and Centerline tracing
strategies, which can be addressed by the “Multi Pass” process!
e.g. in Corel’s PowerTRACE
can be various tracing strategies
applied for the line and the shadow
layer!

• If the individual passes are traced into vector objects, you can take
advantage out of the vector drawing principles like changing the
outline and fill colors, thickness, etc.
• As vector drawing the image will become full scalable without quality
losses in case of cross media publishing intents. (e.g. Web vs. Print)

Process B: Annotation - Emphasis
• To emphasis quickly a specific object resp. area you can use
standard Bezier Drawing functions and you can create shapes on a
separate layer between the line and the shadow pass!
• Or if it has to be more accurate, clone the “shadow” curves from the
original group and make them translucent to generate shadow on the
emphasis area.

Process B: Annotation – Callouts, etc.
• Now standard annotations like callouts, etc. can be added to the
illustration.

Process B: Tip: Single Pass for faster updates!
• If the target and style is fixed and if applicable, you can skip the multi
pass process and render one image with relevant lines, etc. only!
• In a few vector illustration tools you can create shapes as overlay
above raster images!

Process B: Tip: Single Pass for faster updates!
• As long as the camera and light settings are well documented and
stored within the NX CAD file, the same perspective can be render
later on again by technical updates!
• The source raster image has to be replaced only to update the
illustration!
Revision
A
Revision
B

Process B: Explosion
• Exploded Views are honored by the rendering engine!
• Handling the explosion inside the CAD model has the advantage of
associativity in case of design changes!

Process B: Section View resp. Cutout
• Facet model based section views are not honored by the render tool!
• Use the PMI “Section View” function instead!

Process B: Hand Drawn - Effects
• In addition to the pre-defined Lightworks “hand Drawn” functions you
can increase this effect by distorting the individual render pass layers
slightly in the Post Processing step

Process B: See Thru - Effect
• With a photorealistic pass in place,
it is possible to create “See Thru”
effects to visualize interior parts
and components, normally
invisible for the customer.
• In GIMP use…
• Alpha Channel
• Layer Mask
• Opacity setting

Process B: GRID utilization - ISOMETRIC
• In the most vector illustration tools, you can operate with isometric
grids to create the annotation in a more 3D perspective orientation!
• Therefore consider ISOMETRIC view projection in NX CAD as option,
if you have to deal with extended annotations later on!

Process B: GRID utilization – Scene Background
• If you are rendering in “Real Perspective” mode the grid information
have to be transferred too to place annotations accordingly!
• One option could be the pattern repeat utilization of a simple cross as
background image in the scene editor and render a “Cartoon”!

Process B: GRID utilization – Material Grid
• If you need to have a grid at a specific positions inside the model
space you can also use a set of crossing surfaces, which have a
render material with a “Wrapped Grid” Transparency applied!
• Render it as “Cartoon”!

Process B: GRID utilization – Material Grid
• If to have it absolutely accurate and ready for offline dimensioning…
• Create a SOLID grid out of thin “Tube” & “Pattern Feature” functions
and render it as “Lines and Shadows”!

Technical Illustrations with NX CAD NPR support

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