Sign in to follow this  
Holger

what is good quality mesh?

Recommended Posts

Hi guys, I have a question:What is exactly the definition of good quality mesh?I was the one who asked about mesh terrain for South America, I know now that there IS terrain for South America, some of it payware some pieces freeware.I downloaded FSDEM and Slarti, so far I have done terrain for Argentina and some of brazil from S50* to S38*, all I do is use FSDEM and load the tiles, I have done up to 17 Tiles horizontal (corresponding to 1 grade) correct the voids on the terrain, and export the BGL. (I am using LOD 9 and STRM Data)Even though I have not gone up and check this mesh ( will do that tomorrow) I see From the Airport I am stationed now that the improvement is great compared to the default terrain.Now I know that FSDEM cannot correct the Elevated or sunked airports/lakes but if I Happen to find that I will fire up Slarti and correct this.I guess there must be something more to this, what is the next step?I am sure that If one of the respected mesh authors here happen to see my work he/she must say that mine's is not good quality mesh, and that is understandable as this is the first time I do it. What direction should I take to imporove the results?I am not planning to release this mesh terrain to the public, I would be not respectfull to the authors out there payware or freeware that have worked so hard, most of the time without the WYSIWYG tools that we have now, at least not until I find a way to make it better.Guidance needed here. Thanks!

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Hi Gabriel,What is "good quality"? Good question!I would define a "good quality mesh" as an add-on mesh that improves on the default mesh without introducing serious errors, such as flattened areas elsewhere or big trenches or holes.Separately, I would define a "high-quality mesh" as a product that provides the best possible output (a combination of objective accuracy and subjective "believability") given currently available data and processing software.Further, I would keep the issue of compatibility with the default vector and polygon data, such as airfields, lakes, shorelines, etc., outside of this definition. I believe (and hope) that providing a complete "landscape solution", i.e., mesh plus accurate vector and polygon features, will be the new standard in the near future but, currently, most mesh developers and publishers issue "nothing but" the basic mesh.FSDEM, SRTM2BGL, MicroDEM, and Slarti offer "simple" interpolation algorithms to deal with the void areas in SRTM data. These work well for smaller areas (say, up to 5 cells diameter) but for larger voids the procedure should be (1) fill with low-res mesh data wherever possible and/or (2) interpolate with more sophisticated algorithms.In my opinion, John Childs' Blackart is the best pre-processing tool for SRTM data - http://www.terrainmap.com/ . Several months ago I posted a visual comparison of the results obtained with SRTM2BGL, MicroDEM, and Blackart (the thread will be archived but the images missing). It would be interesting to include Slarti and FSDEM in an updated comparison because each utility has special advantages when using SRTM data. However, I won't be the one doing it this time ;-)Generally speaking, to me it is almost more important that the mesh designer's documentation provides clear statements as to the procedure he/she followed and how quality-testing was done, than the specific procedure used. Thus, my definition of both good and high quality mesh also includes the presence of adequate documentation!Cheers, Holger

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this