How To...?

TIPS AND TRICKS FOR SCASM/APT2XX

by Pierre Chabrier


First I want to thank the authors of those two programs Pascal Meziat (APT2XX) and Manfred Moldenhauser (SCASM 1.7). Airport is a great graphical user interface (GUI) that certainly helped many of us to start designing. I still refuse to design a scenery entirely from a text editor (even though the authors of FSASM6.0 told me that's the way commercial scenery are made).

Unfortunately APT2XX does not take full advantage of the capacity of the SCASM compiler, and people usually restrict themselves to what APT2XX can do. The latest patch, APT203, did not really bring any new features.

This non-exhaustive list of "tips and tricks" is design to help us go around some of the limitations of APT2XX. People used to design directly from the SCASM compiler might find those tips a bit too obvious. Some of those tips might seem obvious to almost everybody but others are less and require you to make changes in the SCASM source file. A reminder: *.APT ===> *.SCA ===> *.BGL are the files generated by APT2XX.

The roads have lights at dusk and dawn but not during the night

After talking to Manfred who pointed the line of code involved and after trying several masks, here are the changes you should make to the SCASM file. Look for:

		IfVarAnd(  :TagRoad  028c  0004  )
and replace with,

		IfVarAnd(  :TagRoad  028c  0000  )

Trying different mask can give you lights at night but not at dawn and dusk etc... One easy way of making those changes is to use the wordpad or the DOS editor and the find/replace command (notepad doesn't have a replace option).

When designing a RWY, I find a VASIS option but not a PAPI

I was disappointed too! Even the default scenery uses some (LaGuardia RWY 04). PAPIs are very common in smaller airports/airfields and most of the airports I designed needed one. Manfred told me he made some macros that everyone forgot. Look at this site for: SCXMPL.ZIP (use the search). Add the PAPI macro(s) within the Runway declaration of the SCASM file:

Area( ... )
 ...
:rwy
    RunwayData( 
    ...
      )
    macro(...)
    macro(...)
    Return
EndA
Manfred explains how to place the PAPI(s) at the desired location.

When checking my scenery, the screen goes berserk and/or FS6 crashes

Reminds me my first scenery! You probably have a polygon with more than 127 points. I think Pascal or Manfred mention this but I will go further: try to stay under 110 points. My Orlando scenery had one taxiway with 120 points and it crashed FS6 after a few days. Too late, it was posted. You might have used this scenery with no problem so far, but believe me, you will (I will post a new version in the future). However, you should try to use as many points as possible (but less than 110) because polygons do not connect very well. The goal is to have as few polygons as possible, especially if they overlap. When taxiing or flying you can see that two overlapping polygons don't "move" in phase. It's hard to explain and to show since it's a dynamics problem.

There is nothing you can do about it besides making a conscious effort to limit the number of polygons you use in particular for taxiways. For big airports you often don't have the choice and must use several overlaping polygons, which brings me to the next point...

My polygon connects to itself but the overlapping section is transparent

Indeed, that's what happens when a polygon overlaps itself. The overlapping section reveals the underlying layer, or if none exist, the synthetic tiles (texture) you chose when you started your scenery (see fig. 4a).

Figure 4a

Thus you must create another polygon and play with the layer # (higher # has priority). It is very important to know which polygons should be on top of the other; here I'm talking about taxiways with their blue lights at night. If you choose the same or the "wrong" layer # you'll have problems with those taxi lights (see fig. 4b and 4c).

Figure 4b
Figure 4c

In figure 4b (bad) we have blue dots in the middle of the crossing because the connecting branch has a lower layer #. In figure 4c (good) the blue dots are masked (covered) by the connecting branch which has higher layer #.

I made a big polygone to create a town but the default roads ar covered

Just don't put any layer number and the default roads will reappear. And of course this polygon without layer # is still above the synthetic block!

During the day my taxiways are too visible when the visibility is reduced

I recently posted a message asking for help about this in the FSFW95 forum. The default color code APT2XX selects is 02. As you can see in fig. 6a, the taxiway dots are too visible. Color code 03 (light gray) is better when the visibility is low because the haze has the same color, but then those dots are too visible when the visibility is good. The ideal would be to have a transparent color code but I don't think it's available (if you know something about it please let me know and we'll change this tip). The only color that gives a slightly better result is color code 33 (fig. 6b). It's the color code I now use for all my scenery.

Figure 6a
Figure 6b

The ILS is OK but I have ghost markers or markers at the wrong place

There is a real problem here with APT2XX particularly for airports that already exist in FS6. Richard Bennett (designer of Charlotte, NC) and I discussed this problem and he found that removing the inner marker (IM) helped a lot. For instance when designing Orlando, I had a ghost marker on the 36R approach. I would get OM -> MM -> IM -> MM (the last MM while on the RWY). On approach for RWY 35 the IM would simply be at the wrong distance. In my case I had an exclusion file covering 7x7 NM, with all the exclusion options checked. In Richard's case he had no exclusion file (CLT is not part of FS6 default). The curious thing is that by removing all the IMs, all the markers were now at the right distances, including the IMs!!! (they should not exist since they were removed!!). This is still a complete mystery for me but it works.

How do I connect a road from my airport to an FS6 default roads

This one is really not a trick! But someone asked me once... Go in FS6, slew on the ground to the existing road you want your road to connect to, and write down the exact coordinates. In APT2XX terminate your road at these coordinates.

Aside APT2XX and SCASM

I would like to add a word of caution about VOD25. We all know that 3D objects are frame rate killers depending on their size, texture and number. But I would advise to avoid using API objects created with VOD25 in Apt2XX as they don't seem to be compiled in the most efficient way (this is my guess). As a test, you can place a gray cube with 5 walls (no floor, no texture) in an empty scenery. Then create the same cube with APT2XX using the adjustable 3D object "Hangar 1" (same size, same color, no texture etc...). The frame rate difference between the two objects in the same environment is dramatic.

That's it for now. I hope designers will send their own tricks to FlightSim.Com and augment this section. Don't forget to test your scenery for a few days before posting it and... Happy flying!

Pierre Chabrier
pierre@grove.ufl.edu


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