CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Mesh Generation & Pre-Processing Software > Pointwise & Gridgen

Incorrect projection

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By dgarlisch

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 27, 2017, 18:19
Default Incorrect projection
  #1
New Member
 
jared
Join Date: Mar 2015
Posts: 17
Rep Power: 9
jsagaga is on a distinguished road
I'm fairly new to Pointwise and still learning how to use it. I'm currently trying to create an unstructured surface mesh for a wing in which the CAD was not created by me. My question is about the projection of the connectors onto the curved surface on trailing edge of this wing. I've tried creating an abundant of connectors/points onto it and tried spacing it evenly hoping for the connectors to conform more to the curvature of the database. I'm not sure if it will be a problem if I continue to generate the mesh and place it the solver that I'll be using, which is FUN3D. I only think it will be a problem just from looking at the projection of the connectors to the database surface being off. I've attached the images below hoping it showcases the issue I'm facing. In the images, green/teal colored lines represent the connectors and the off white lines represent the database.

Thank you!
Attached Images
File Type: jpg Connectors and Database ONLY.jpg (13.5 KB, 11 views)
File Type: jpg Connectors, Database, and Unstructured ONLY.jpg (22.5 KB, 14 views)
File Type: jpg Close-up.jpg (196.1 KB, 13 views)
jsagaga is offline   Reply With Quote

Old   October 30, 2017, 09:20
Default
  #2
Member
 
Kirill-MIPT's Avatar
 
Kirill Borodin
Join Date: Mar 2016
Posts: 60
Rep Power: 8
Kirill-MIPT is on a distinguished road
Hello! The type of projection may be wrong. Try using linear projection
Kirill-MIPT is offline   Reply With Quote

Old   October 30, 2017, 10:40
Default
  #3
Senior Member
 
David Garlisch
Join Date: Jan 2013
Location: Fidelity Pointwise, Cadence Design Systems (Fort Worth, Texas Office)
Posts: 307
Rep Power: 13
dgarlisch is on a distinguished road
This is probably just a rendering issue.

The long curve is drawn by OpenGL as a series of straight line segments. The default settings in Pointwise are probably not working on this long curve.

The grid points are actually on the "true" curve. They do not match visually with the curve because there are many more grid points than there are OpenGL render points. Increasing the display resolution will make the grid and curve match more closely.

You can change the render resolution:
  • Select the curves/surfaces you want to adjust
  • Menu View, Attributes...
  • Open the Advanced section
  • Increase Triangle Density (range 1-256) to make surfaces "smoother"
  • Increase Line Density (range 1-256) to make curves "smoother".
  • Press Update Entity Display

I have attached an image showing a highly exaggerated representation of what I am describing and a zipped PW file that shows this concept using connectors on a curve.
Attached Images
File Type: png OpenGL-vs-Grid-Rendering.png (4.8 KB, 13 views)
Attached Files
File Type: zip OpenGL-vs-Grid-Rendering.zip (25.0 KB, 1 views)
jsagaga likes this.
dgarlisch is offline   Reply With Quote

Old   October 30, 2017, 11:46
Default
  #4
New Member
 
jared
Join Date: Mar 2015
Posts: 17
Rep Power: 9
jsagaga is on a distinguished road
Quote:
Originally Posted by dgarlisch View Post
This is probably just a rendering issue.

The long curve is drawn by OpenGL as a series of straight line segments. The default settings in Pointwise are probably not working on this long curve.

The grid points are actually on the "true" curve. They do not match visually with the curve because there are many more grid points than there are OpenGL render points. Increasing the display resolution will make the grid and curve match more closely.

You can change the render resolution:
  • Select the curves/surfaces you want to adjust
  • Menu View, Attributes...
  • Open the Advanced section
  • Increase Triangle Density (range 1-256) to make surfaces "smoother"
  • Increase Line Density (range 1-256) to make curves "smoother".
  • Press Update Entity Display

I have attached an image showing a highly exaggerated representation of what I am describing and a zipped PW file that shows this concept using connectors on a curve.
Thank you so much dgarlisch! Your explanation on my issue makes perfect sense and it worked without a hitch when I applied it!
jsagaga is offline   Reply With Quote

Old   October 30, 2017, 11:47
Default
  #5
New Member
 
jared
Join Date: Mar 2015
Posts: 17
Rep Power: 9
jsagaga is on a distinguished road
Quote:
Originally Posted by Kirill-MIPT View Post
Hello! The type of projection may be wrong. Try using linear projection
Appreciate the help Kirill-MIPT! I might try that for a different case.
jsagaga is offline   Reply With Quote

Reply

Tags
curved surface, mesh, pointwise, projection, unstructured mesh

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
SIMPLE vs Pressure Projection for Steady-State Incompressible matdehaast Main CFD Forum 0 September 4, 2015 08:56
[blockMesh] BlockMeshmergePatchPairs hjasak OpenFOAM Meshing & Mesh Conversion 11 August 15, 2008 08:36
projection method sudhakar Main CFD Forum 4 December 8, 2007 02:25
LiftDrag utility from v12 to v141 cfdphil OpenFOAM Running, Solving & CFD 2 December 5, 2007 06:49
A Second-Order Projection Method for Incompressibl Ivan Main CFD Forum 5 April 29, 2001 08:27


All times are GMT -4. The time now is 09:22.