Sign in to follow this  
Guest bones

HYP (LWM) BGL's again

Recommended Posts

Having rebuilt a coastline section with CLM I've discovered that the mesh still conforms to the default FS coastline. Removing the default HYP***.BGL file for the area fixes this - but this "fix" also allows the LOD13 land cells to reappear in the sea.Is there a simple solution?boneshttp://fsaviation.net

Share this post


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

Hi bones.http://ftp.avsim.com/dcforum/DCForumID10/1884.htmlWhen an area is flattened by an LWM, it destroys the underlying mesh. There is no way to "exclude" that effect. We can turn the water to land or land to water... but the flatten remains.Deleting an HYP bgl is not a good soultion. A typical HYP covers hundreds to thousands of square kilometers, and erasing them would require you to rebuild the other areas with new LWM water with elevations.So remeshing is probably your only choice.The idea of remesh has been discussed quite a few times. Ground2k even offers a use of this, although I haven't really tested it... it uses LWM flattens, I believe.Area16 Commands can also be used to remesh as well, and may actually have some advantages. Steve Greenwood has a utility to help create remeshing: http://www.fs-traveler.com/flatten.html Or you might feel comfortable writing them directly in SCASM code.If Area16 Commands( SCASM ) or LWM flattens, it seems to make little overall difference... except we don't know if Area16 will be supported in future versions. Some of these commands from FS2000 and CFS2 no longer work correctly, if at all. LWM flattens will most probably work in FS2004. My guess is FS2004 will allow Area16 as it exists now.Dick

Share this post


Link to post
Share on other sites

You write well - I actually understood all that. :)I agree that disabling the HYP file isn't a good option but if I don't the mesh conforms to the default FS coastline - it overrides my new coast. It's awful to look at because the HYP LWM's result in a cliff face about 500ft inland (the original FS coast was way out).So, with my new coast loaded and the HYP file active I get my coastline but the mesh is still flattened by the LWM's of the default FS coastline.With the HYP disabled the mesh now gets flattened by my own coastline correctly but, as you say, I've lost all the coastlines elsewhere in the 180nm x 300nm (approx) area and I get land filled cells appearing..I don't understand why the coastline in the HYP files still control the mesh flattening rather than my own LWM's (set to Layer 1)..The mesh I'm using is accurately located..boneshttp://fsaviation.net

Share this post


Link to post
Share on other sites

Hi bones.This is one aspect of the LWM structure that really needs to be changed for FS2004... I don't know if they will. We can remask an area to land or water with LWM's, but the original elevational setting of those default LWM polys remain. There is no way to exclude it.Other than replacing the original set of HYP files, your only recourse is to remesh. This uses flattens ( either LWM transparent flattens, or Area 16n SCASM coded flattens ). The process isn't too hard for a small area. What you do is to draw tiny polys with new elevations that act like tent poles.. propping up the flattened mesh. LWMs can actually be tiny 2-point polys, if desired. I think Area 16 elevations need 3 points minimum. I usually use 2 point LWMs. The effective size of these polys seems to be controlled by the mesh size LOD. So an LOD11 mesh will respond to a tiny poly better than a LOD6 mesh would. For LOD6, a larger elevational poly size may be needed. The drawing of these flattens to re-establish a mesh is more art than science. It could take dozens to hundreds of these polys for a large area. It seems to me the effective size of an LWM poly needs to be a minimum of 16 units long of the LOD13 Area's 256x256 grid. A 16 unit long 2-point LWM line is about LOD9 grid size. By grid size, I mean the distance between 2 verticies of the underlying mesh. An LOD6 grid would have verticies of the mesh at every 128 LWM Area points. If you can imagine the 256x256 LO13 Area as having verticies... like the points on dice. 3 rows of 3:0....0....0.0....0....0.0....0....0You should be able to place polys at those points, and simulate LOD6 mesh. Size of the polys? I think effectively determined by the underlying mesh... but I'd start with 8x8 polys ( or 8 point distanced LWM 2-point polys ), and see what happens. I wouldn't be surprised if the polys needed to be 16X16 in size. So the 0's in the above diagram would represent the 16x16 polys, and where they'd be placed on an LOD13 LWM Area.An LOD7 remesh grid would be 5x5 verticies... separated by 64 LWM points. LOD8 remesh grid would be 9x9 verticies, separated by 32 LWM points. LOD9 is 13x13 verticies, separated by 16 LWM points... and probably as fine a mesh as you need to go. You'll have to experiment.SCASM Area16 remeshing would be a bit more difficult to compute where you'd like to place the polys to stick them on a LOD sized grid. Perhaps a program might be needed to do that automatically. The latest version of SCASM has some LWM support... I haven't tried it yet. :(This is a rather unexplored area... not much research done to determine the rules for flatten poly locations and sizes, for effective remeshing.Dick

Share this post


Link to post
Share on other sites

Thank you yet again Dick..Printed out for much careful study...Like most other things this started out as an airfield rebuild. However the airfield was right on the coast and the project's just got deeper and deeper.. I was talking to someone recently who actually flies in FS2002. I must try that again some day. :)boneshttp://fsaviation.net

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