August 1, 2014, 10:57
READ FIRST: How to give enough info to get help
Join Date: Mar 2009
Location: Ottawa, ON, CAN
Rep Power: 13
This post is provided to forum users seeking help in the Pointwise sub-forum with some general advice to better ensure a) someone will answer your cry for help b) you give enough information so the helpers can help the helpees.
I borrowed and pillaged from the existing "How to give enough info to get help" threads elsewhere on these forums (mostly from Niels Linnemann help page on the OF wiki). So kudos to those trailblazers.
Before diving in, note, one doesn't necessarily need to follow every single piece of advice to the letter. These are just suggestions to increase your chance of getting a solution to your Pointwise meshing problem. So of course the closer you follow it, the better chance for success and happiness. See the sample posts at the bottom for examples of successful threads.
1. Before posting - Do your homework
- Give the impression that you've invested at least as much time in seeking an answer (previous research, alternate methods, pictures, etc) as you expect others to invest. People are answering in their spare time, free of charge. This is the single most important tip.
- Use the search-function of the message-board (or google with site:cfd-online.com) to see if someone has encountered your (or a similar) problem previously. If so, let people know what you have found and why it didn't help. Show that you have thought about your problem.
- If you have the feeling that your problem is unique/new: start a new thread.
- When starting a new thread give it a meaningful title (threads like "Hlp plz!" or "I'm a newbie" are very unlikely to draw much help). See #3.
- Don't hijack threads, i.e. don't ask a question irrelevant to the thread topic. This is just general forum courtesy. Refer #1 for new posts.
- Reviving very old threads is unlikely to lead to a response. If it's more than a few years old, refer to #1 and start a new post.
- Be polite.
- Be precise but be brief. Make sure a large audience can understand your problem.
- You can of course post in whatever language you prefer but English is likely to get more responses.
3. Posting Tips
- Prepare for getting help: The forums do not provide large file uploads so using a cloud storage service (e.g. dropbox, imgur, slideshare, etc) and posting a public link to the picture/file makes it a lot easier to share files/pics/project files.
- Start by giving a relevant and clear thread title, e.g. "Structured mesh smoother: difficulty controlling boundary orthogonality", "T-Rex: parameter suggestions for improving mesh quality" or "Scripting: tips for automating structured block assembly?". This little information tells us what basic algorithm you're using and what you need help with.
- Fully describe your application and the approach you are using to mesh it. Unless it is a really simple problem post a picture. Pictures usually say more than a thousand words can. If you can't post due to sensitivity restrictions create a sample case to reproduce the same issue and post those pictures. In most cases, posting a picture will result in a quick answer. This helps immensely when trying to visualize whats inside your head. Here's a couple of tips for doing so:
* Overview of the entire model: Take some time to hide or change the Shading and Line rendering modes particularly for domains to make it easy to understand what we're looking at. See the first image attached of a structured mesh of a sphere in a rectangular duct where I've changed the Line mode of interior domains to Boundaries to make it easy to understand the overall model. This effect could also be achieved by assigning entities to layers and toggling the visibility of the relevant layers. - Problem description: What's the problem? What have you tried to fix your problem and why hasn't it worked? What type of mesh (structured, unstructured, hybrid, TRex, etc)? If possible, provide a step-by-step account of what led to the problem.
* Close up of region of interest: Zoom and/or change the model orientation to best highlight the region where you're question is occuring.
* Take screenshot of entire Pointwise window (optional): If you're working in a mode, by taking a screenshot of the entire application window you will also include the relevant settings and parameters used for that operation. This can be done in Windows and modern Linux versions with ALT+Printscreen buttons. On Mac the equivalent is CMD-CTRL-SHFT-4, then space, then click the Pointwise window. See the second image attached where I'm smoothing the structured domains on the sphere.
- Relevant output: If there's potential helpful info in the message, copy and paste into the post. If it's a scripting question/problem post the code (clip it to the relevant parts). Use the CODE marker to make it stand out.
- Algorithm settings: Extrusion, smoother, T-Rex, etc all have a plethora of parameters that control their behavior. Report the parameters used for any/all algorithms used.
- Post the project (.pw) file: Native Pointwise files can't be attached to posts so use a cloud storage service to temporarily host it. This will most definitely result in the fastest answer.
- Pointwise version
Rather than make up an example here are a couple of good examples that resulted in happy customers:
Generate a c topology mesh of an airfoil
Extruding a domain with an overlap
5. Last but not Least
- It's YOU who has control of the mesh: just because Pointwise created/exported your mesh doesn't mean it will necessarily run in your CFD solver BUT just because your mesh doesn't run in your CFD solver doesn't mean it's Pointwise's fault. Having said that, asking for help on improving mesh quality are great questions to ask here.
- Give and ye shall receive: treat the thread like a conversation. People will engage if the dialogue is two-way.
- For the benefit of everyone: avoid sending private messages. It's better if discussions are for everyone to see so that we all benefit.
Last edited by cnsidero; August 5, 2014 at 08:25.