• A Rookie's View Of Terrain Mesh

    A Rookie's View Of Terrain Mesh

    By Mike McCarthy (15 March 2009)

    I hope that the article you're reading now will spark discussion in Outer Marker and/or the FSX forums here on FlightSim.Com by people who know much more about the subject of terrain mesh than I do. And please bear in mind that I'm most definitely biased whereas Bill Stack is not. Here's what I mean about my biases...

    I've known FS Dreamscapes lead developer Dean Mountford for about two years and consider him to be a good friend. It's friendship that motivated me to write this article. However, I know very little about the subject of terrain mesh and would not be able to write a valid in-depth review of anybody's terrain mesh products much less those of FS Dreamscapes. Therefore my remarks are those of a terrain mesh rookie and perhaps shouldn't be given as much weight. Finally, Dean Mountford has read a draft of this article for purposes of fact checking and while he didn't request any changes, that's perhaps because I wrote the article having in mind what I believe his position to be. So I'm definitely a Dean Mountford fanboy and you must take this into account.

    Those things said, common sense tells me that while Bill Stack's recent review here is the truth, it isn't necessarily the whole truth ... And the missing truth is what lies at the heart of the FS Dreamscapes product in question. Here's what I mean...

    FSX represents a considerable enhancement of the concept of terrain mesh as we knew it in FS2004 and earlier versions of Flight Simulator. As I recall the now-closed ACES Studio had a 3-4 people team entirely dedicated to this issue while FSX was being developed. That's how important they considered the matter of terrain mesh to be.

    I believe that the work of FS Dreamscapes represents, among other things, a natural extension of the enhanced terrain mesh resolution presented in FSX. ACES made the FSX terrain mesh to be of higher resolution and increased accuracy. If nothing else FS Dreamscapes has made important further advances in both those areas.

    Now you might say "So what?", which is effectively what Bill Stack said, or so it seemed to me upon reading his review. But you might also say "If what ACES did is good, then what FS Dreamscapes did is even better." So let's look at where these kinds of improvements might be important to some (though by no means all) users of FSX.

    It would be absolutely true to say that from 35,000 feet there probably would be no important visual difference between the stock FSX mesh and that of FS Dreamscapes. However, even jet jockeys do approaches and landings. On final some of us might be just as interested in seeing terrain detail as we are in seeing airport buildings or airport traffic.

    In fact, I'll point out that at my home airport KDEN, a few months ago we had a real world 737 takeoff accident in which the aircraft swerved off the runway and broke up exactly because the actual terrain alongside the runway is somewhat hilly. In contrast, to my knowledge the FSX terrain around KDEN is essentially flat.

    What happened here was that the aircraft went over the edge of a shallow draw, became briefly airborne as a result, and broke up when it impacted the other side of the draw. In flat terrain this would not have been an important accident. The nosewheel would have been ripped off for sure but most likely nothing else would have happened. But in the real world of the rolling prairie hills around KDEN the accident was serious.

    Is it important that users of FSX have this kind of detail available around various airports? I don't know -- you tell me. I'm not a fan of scenery, but many other people are.

    Similarly, consider Florida. It's mostly flat, right? As I recall, the highest point in Florida has an elevation of only about 350 feet. Yet Florida has highway overpasses with built-up berms, and ditches alongside highways, and depressed traffic separation areas between opposing lanes. Do you want to see those things portrayed realistically even in Florida? Is that kind of detail important? Again, I don't know. Again, you tell me.

    What I do know is that Bill Stack's review did not consider this kind of detail. He appeared to be concerned only about how things looked from several thousand feet away. He remarked that the difference between FSX and FS Dreamscapes was at most a few meters, or words to that effect, yet we've just seen how terrain height differences of only a few meters can make the difference between life and death.

    Drawing on my own experiences, I frequently make test flights through the valleys and mountain passes of the Rocky Mountains immediately to the west of Denver, Colorado. I have to de-rate the FSX terrain mesh because of computer limitations, but I can easily see how my "as real as it gets" experience would be enhanced by seeing small rock outcroppings instead of only large ones.

    So that's my perception of what FS Dreamscapes has done. They've provided much higher resolution imagery that does the stock FSX.

    Is this important to many FSX users? Again, I don't know.

    But if we make an analogy to digital photography, which is an area where I do have some expertise, it's probably like the difference between a 2 megapixel camera and a 10 megapixel camera... And that difference would certainly be important to me because my photographer's eye is able to see that kind of difference in even casual photos printed in medium size format.

    Mike McCarthy
    [email protected]

    Discuss this in the Outer Marker message forum

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