openFoam Visulation Rendering using BlenderopenFoam Brisbane Users' Group

19th June 2014

Objectives

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

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"

Blender

• A few basics - please refer to Matt Cragun's presentation:

http://www.openfoamworkshop.org/6th_OpenFOAM_Workshop_2011/Program/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

The Workflow

Rendered image

Blender

X3D 3DS

SketchUp GeometryParaView

VTK

openFoam

Files Provided SketchUp and 3DS files,

including textures

openFoam CFDresults converted

to VTK format.

Download from:https://s3.amazonaws.com/cfdresultspublic/oF+Rendering+using+Blender.zip

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

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)

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

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

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

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)

Blender

Let's remove the tube shadows:

• Select ShapeIndexesFaceSet

• Select Material panel• Untick Traceable

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

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)

Blender

Modify as desired to improve camera position, lighting position and intensity.

Then:• Change resolution to

100% (Render panel)• Render (F12)• And Save (F3)

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

Happy Rendering

Thank you for your time and attention...

Please, tweet your rendering pictures to @HibouSoftware

and

on Fridays use #simulationfriday