FSX Ground Polygon Wizard in ModelConverterX – empty bgl?

[Fletch146]

I'm in the middle of building Hatfield aerodrome (where I used to work). I've been using MCX to convert models of hangars etc that I built using Sketchup, and Wings3D (I haven't got around to learning modelling in Blender yet). I haven't had any trouble with MCX so far. It's been great for modelling.

I want to make the ground areas more high def but I've got stuck trying to use the Ground Polygon Wizard in ModelConverterX. I followed a Youtube video (by Soarfly Concepts Scenery) on how to make the ground polys. This method uses FS Earth Tiles, ADE, Sketchup, Model Converter X and an image editor (he used Photoshop but I used Gimp).

Everything went well until I got to the stage of saving the bgl file using MCX's GPW. It produced an empty bgl of around 60kb instead of the original's 6.49mb. The file clearly doesn't have the bmp's within the bgl, but when I move the bgl into MCX it reads the bmps (residing in a working folder called Texture) and shows up on the MCX screen with the path to loaded textures (see screenshots x3). So the bgl is acting like an mdl file. Is that a clue to anyone?

I went through his video again to see if I missed a stage but didn't notice anything. I've tried a few changes to parameters but still same results. It appears that I've performed the stages ok before getting to MCX, as the ground poly shows up there but just doesn't convert to a full bgl. I even resaved the airfield as a dae (minus the two HD ground images I'd added) from Sketchup and tried again. But it just created an empty bgl again. I dragged this bgl onto the MCX blue workspace and it showed up ok, by reading the bgl's in the Texture folder as before.

Is the GPW playing up or is there something I'm missing? Am I missing out a stage? Any help and ideas to troubleshoot would be gratefully received, as would a link to a clear tutorial on using MCX GPW successfully.

Note:
The Youtube video seems to use a v1.4.xxx.
I used MCX v 1.4.0.0.873462e DEV 8/7/2020
I also tried v 1.4.0.0.5de74c65 DEV 12/6/18

Both give same result. I also tried v1.3 but that asked for SCASM(?) path (I didn't find such a file in FSX SDK). Anyway I've gotten used to using one of the v1.4's and would rather stick with the newer version.

 

[tgibson]

I don't understand. Ground polygon BGL files never contain the textures within it, just the mesh (which can be pretty small). You say you load this BGL file into MCX and it loads as it should, including textures.

So place this BGL into an active scenery folder in FS, and place the textures into the adjoining texture folder (in FS compatible format), just like any other scenery, etc.

 

[Fletch146]

Thanks for the advice. That helped a lot.

I see what you mean but I'm still a little confused on this.

The original BGL, created using SbuilderX, is over 6mb and seems to contain all the tiles/info that make up the airfield poly. This is located in Scenery folder of my Hatfield airfield folder within FSX Addon Scenery. There are no additional image files in the corresponding Texture folder. I thought therefore the airfield image ground poly info must all be in the original BGL. I didn't put in any other files to display the SBX airfield ground in FSX.

I previously added a couple of higher res patches of ground, as a test, using ADE. That method appears to save the added ground images as separate BMPs and puts them in the airfield texture folder, with a bgl file within the scenery folder to load them over the main airfield bgl.

As I understand it, the ground polygon wizard in MCX takes the original tiles, adds my hi res ground images (departure aprons) and saves those as one bgl file, in layers. The wizard says “Select output BGL file” so it seems to create one bgl file. The Youtube video didn't mention that the tiles are converted to individual small BGLs which then have to be placed in the airfield texture folder in FSX.

I've copied the MCX created BGL and BMP files to FSX as you suggested and removed the original BGL-. That worked and my added apron surfaces show up (see screenshots below). You can see it looks better than the original base layer. Though not as hi def as payware airports, not bad for the intended freeware.

The only thing is instead of getting the airport area displayed by:
one BGL @ 6.52mb + 2 two apron files @ 1mb total (3 files)

I now have the same area displayed by
one BGL @ 78.0kb + 62 BGLs @ 16.2mb total + my two small files @ 1mb total (65 files).

I'm struggling with my model making to get the frame rate up (another snag subject for a later thread elsewhere) so I'm wondering do these 62 BGLs count against total drawcalls?

It didn't seem to make any change to my rubbish frame rate so far but it might (or not) by the time I finish resurfacing the whole airfield.

Any more clues on the operation of MCX GPW would be appreciated.

Thanks again.

 

[tgibson]

Hi,

I think we are talking about two different things here. A ground polygon is a relatively small area, and can be any shape. The textures are not contained in such BGL files. That's what MCX creates in the GPW. What SBuilder creates is probably photoreal terrain, based on some satellite/aerial imagery. It is always in rectangles, and to my knowledge is never called things like "airport polygon" or "ground polygon". It is "photoreal terrain" or "aerial photo scenery". The textures CAN be contained in such BGL files.

While MCX may be using your SBuilder photoreal scenery textures as the textures for the ground polygon, once they are applied to that ground polygon you must follow the rules for ground polygons and include those textures in the adjoining texture folder.

 

[Fletch146]

Thanks for the explanation. I think I'm starting to see how it's done.

I think the thing that confused me was that the MCX wizard also cuts up the airport image into tiles resulting in small BGLs in the Texture folder. I thought it was going to leave the main image whole (as an earth tile bgl) and only save my added images to the Texture folder as polygon(s), the way ADE seems to do it.

SbuilderX and FSEarthTiles download the tiles from a mapping site and assemble them into a BGL, which is to be placed in the Scenery folder. And I now get it that they are not termed ground polygons.

Whereas MCX is dealing with placing my higher res images onto ground polygons that are displayed above the earth tiles when in FSX. These are saved as several BGLs. and are to be placed in the Texture folder.

Now that I know what it's going to do I'll get on with creating the taxiways etc see how that goes. Thanks.

 

[tgibson]

Small BGL files in the Texture folder? I don't think that BGL files could be read by FS there, so I don't know what they are doing there.

 

[Fletch146]

I made a mistake there. I meant to say BMPs not BGLs in the Texture folder.

(I have managed to create some more ground surfaces and resaved through MCX GPW so the airfield is starting to look a bit better when taxiing.)

To get the whole airfield areas for the few airfields I'm working on I used SbuilderX then tried FSEarthTiles. These two programmes download the areas in smaller tiles then stitch them together into one BGL file. I think that's why my original BGL was 6.4mb. This file is placed in the Scenery folder of my airfield and no files are created to put in the Texture folder, which only had my model BMP files.

The original airfield scenery BGL looks ok from about 1000+ but when landing / taxiing the ground is very indistinct so I first tried using ADE to place a test ground image of higher res. This worked by creating a small BGL for the scenery folder which points FSX to the Texture folder which has the corresponding image file (Run Stand Hex1.bmp). Between them these files create the higher res small area ground poly.

Crucially ADE does not touch the main airfield image BGL. It seems to work out the mesh and lat long for the image (e.g. run stand) then just blends that BMP image over the airfield image. The only thing is it's not easy to get the run stand or whatever in the exact spot within ADE (without the airfield image).

I discovered only the other day that MCX can create and place ground polys also. So I gave it a try.
MCX is great and did the job, but I was confused because it achieved the result by a different method.
Yes each added high res image (run stand etc) is created as a small BMP and put into the Texture folder, with a small BGL for the scenery folder, but MCX GPW also chops up the airfield image into tiles that also go to the texture folder. This total is now 16mb BGL x 62 tiles (+ my small high res BMPs). So I wasn't sure if that method with more files meant a hit on fps compared to ADEs method.

I'll maybe try saving only the added high res run stand etc from Sketchup (- the main airfield image) and try MCX GPW again. The video I watched showed to cut the main airfield up into about 16 tiles, which MCX chopped so I'll try changing Sketchup setting to only four tiles to see if that reduces files and sizes.

Also I've hit another problem, which is nearly fixed. SbuilderX and FSEarthTiles use the top bottom, left and right lat longs from the airfield image to place it in its correct location in FSX, whereas MCX GPW uses the airfield runway centre. These don't quite match up and put the airfield image slightly out by a few feet. This wouldn't matter if you use only MCX then place all the models on the airfield. But I'd already placed most building, hangars etc so I had to go back into Sketchup and carefully move the centre manually so it would line up with the rest of Hatfield. I still had to move my models a bit. So that's something others will want to avoid.