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 Technologies 2 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 Simulation Team - Collaboration

Assembly Instructions Internal Visualization (e.g. SAP)

Sales / Service Tools

Work Officer

CAM / CNC

Technical Illustrations

Technical Service

Marketing

External Studio Web 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”!

Engineering

Technical Illustrations with NX CAD NPR support