This document discusses using Blender to generate high resolution renders of openFoam CFD results. It outlines the workflow of exporting openFoam data to VTK format using ParaView, importing it into Blender along with 3D geometry files, positioning and lighting the scene, and rendering the final images. The key steps are converting CFD results to VTK, using ParaView to extract streamlines and export to X3D, importing files into Blender, aligning the geometry, adding lights, and rendering images of the CFD results visualized on the geometry.

1. openFoam Visulation
Rendering using Blender
openFoam Brisbane Users' Group
19th June 2014

2. Objectives
• Learn how to
generate high
resolution render of
openFoam CFD
results using Blender

3. Thanks
• CAEdevice www.caedevice.net for enabling the use of
his design geometry
• KVRC www.khamsinvirtualracecarchallenge.com and its
partners: Competition Car Engineering and Hibou
Scientific Software
• Matt Cragun, Total Sim USA for his presentation "Data
Visualisation and Rendering with Blender and VTK"

4. Blender
• A few basics - please
refer to Matt Cragun's
presentation:
http://www.openfoamworkshop.org/6th
_OpenFOAM_Workshop_2011/Progra
m/Training/cragun_slides.pdf
Be prepared, the learning
curve is steep...
Shortcut Action
RMB Select
Shift+MMB Pan
Shift+D Duplicate
G Grab (to move an
object)
R Rotate
(G, R) >> (X, Y, Z) Specify the axis to
be used to
move/rotate object
X Delete
F12 Render
F3 Save image

5. The Workflow
Rendered image
Blender
X3D 3DS
SketchUp GeometryParaView
VTK
openFoam

6. Files Provided SketchUp and
3DS files,
including textures
openFoam CFD
results converted
to VTK format.
Download from:
https://s3.amazonaws.com/cfdresultsp
ublic/oF+Rendering+using+Blender.zip

7. ParaView
• Start ParaView;
• Open files:
– bc_body_480.vtk
– bc_frontwing_480.vtk
– bc_rearwing_480.vtk
– bc_wheelback1_480.vtk
– bc_wheelback2_480.vtk
– bc_wheelfront1_480.vtk
– bc_wheelfront2_480.vtk

8. ParaView
Let's create streamlines:
• Open file: internalMesh.vtk
• Select the internalMesh.vtk
object;
• Activate the Steam Tracer
filter;
• Change the Steam Tracer
parameters to:
– High Resolution Line
Source
– Point1: (-1.0; -1.2; 0.25)
– Point2: (1.0; -1.2; 0.25)

9. ParaView
And color them:
• Select the StreamTracer object;
• Select the Tube filter;
– Radius: 0.005
• Change the color variable to "U"
Then do a little bit of house keeping
and export:
• Hide the car geometry;
• Select Edit View Option:
– Turn off Orientation Axes
• Export scene as X3D

10. Blender
• Start Blender
• Delete the default cube in
the middle
• Import
RenderingRoom.3ds
• Import CAEdevice.3ds
• Rotate (R) and move (G)
the car to align properly:
– R >> Z >> -90
– G >> X >> 1.5
– G >> Y >> 5

11. Blender
• Import results.x3d saved from
ParaView
• Delete by right-click in the
object view and select Delete:
– TODO to TODO.006
– ViewPoint
• Select the ParaView object
(ShapeIndexedFaceSet);
• Rotate and position:
– R >> X >> 90
– R >> Z >> 90
– G >> X >> 1.5
– G >> Y >> 5

12. Blender
• Position camera
– G >> X >> -8.5
– G >> Z >> -4
– G >> Y >> 8.5
– R >> Z >> -90
– Rotate so that car is in
the camera view point
using View>Camera
And Render (F12)

13. Blender
Let's remove the tube
shadows:
• Select
ShapeIndexesFaceSet
• Select Material panel
• Untick Traceable

14. Blender
Add lighting:
• Select existing
light;
• Copy (Shift+D);
• Move the copied
light (X, Y, Z);
• Repeat above step
twice for key and
fill lights
Fill Key

15. Blender
• Set the lights as
follows:
– Initial light (lamp):
• R >> Z >> -90
• Sun
• Energy: 1
– Key light:
• Energy: 0.4
– Fill light:
• Energy: 0.1
And Render (F12)

16. Blender
Modify as desired to
improve camera
position, lighting
position and intensity.
Then:
• Change resolution to
100% (Render panel)
• Render (F12)
• And Save (F3)

17. Blender
• Repeat with showing
the pressure
distribution on the car.
• Tricks:
– In ParaView:
• Group the various car
parts in one dataset
• Coarsen the mesh
using Quadratic
Clustering filter

18. Happy Rendering
Thank you for your time and attention...
Please, tweet your rendering pictures to
@HibouSoftware
and
on Fridays use #simulationfriday