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Sketchup Geo-Located Models and Grouping

M

MikeD096

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41
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us-newmexico
I'm in the process of placing around 60 taxi/guidance signs for my airport project. All of the taxi signs use the same texture sheet, so I thought it might be beneficial to place groups of signs into a single Sketchup model. This way twenty or so signs would only have one drawcall, vs twenty individual models making one drawcall each. Plus I then would only have to place two or three taxi sign models vs hand placing each one via ADE or whatever.

- Am I correct in this thinking or does it not matter whether I group the signs?

Since I'm placing several taxi signs in one model, I needed a good way to find the exact location of each sign, in an efficient manner. To do so, I utilized Sketchup's geo-locate feature. Since there is only one geo-location point, and it sets the center of the axes at that point, I chose a visual point (corner of a runway - Red X in attached), then added geo-located images at points down the runway where signs exist, placing my signs at their exact spots (blue circles). After spending a few hours on this process, I then realized I had no idea how to place this geo-located model in FSX! So here lies my next question...

- In this particular instance, knowing the GPS of the center of my axes, how would I go about placing the model in the correct spot in FSX? I'm familiar with the process of exporting and using MCX to convert, etc. Would simply using the same GPS coordinates of my axes result in accurate placement of the MDL?

I will be removing all of the ground images and related materials prior to exporting, so that it is only the signs and the texture sheet.
 

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  • RW_4-22_Signs.png
    RW_4-22_Signs.png
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Hi,

For the drawcalls it does not matter if you export as one or models. As long as they all use the texture texture and drawcall batching is enabled even multiple models will be one drawcall.

About the placement, if you do it in SketchUp already and then export to kmz the coordinates are kept. You an then directly export to bgl from modelconverterx and keep the placement.
 
During some testing, I found some interesting issues.

You can export all the models as a single collada, run it thru MCX, and it fits fine in FSXA. However, the GPS coordinates and heading do not match 100% from Sketchup to FSX. This was true even when exporting as KMZ.

For this model, I had to make the following adjustments for everything to line up:
Longitude: xx.138644 --> xx.138671
Latitude: -xxx.809077 --> -xxx.809073
Heading: 358.96 --> 358.88

It took a lot of back and forth between MCX and FSX to make the necessary alignment adjustments, which is very unfortunate and time consuming. I really wish this was a direct 1:1 correlation.

It was nice placing the signs in their exact spot in Sketchup, and having them grouped into a single file, but the inaccuracy between Sketchup and FSX results in too much time fine tuning the alignment. So now I'm wondering if exporting the individual signs, converting to MDLs, then compiling a BGL with location information in XML for each sign will be more accurate, and take less time?

There is also the option of exporting to MDL, creating a Library, then placing with ADE or other apps.

So many different options/workflows! And what works best for placing a single item is not always the best for placing 40+ items.

Oh yeah... if you do place several items over a long distance in a single Sketchup file ... dont forget to correct for FSX Earth curvature! ;)
 
You can export all the models as a single collada, run it thru MCX, and it fits fine in FSXA. However, the GPS coordinates and heading do not match 100% from Sketchup to FSX. This was true even when exporting as KMZ.

For this model, I had to make the following adjustments for everything to line up:
Longitude: xx.138644 --> xx.138671
Latitude: -xxx.809077 --> -xxx.809073
Heading: 358.96 --> 358.88
Click to expand...
Depending on where you initialize your project in Sketchup, the initial 0,0,0 axis is hardcoded and can not be changed that I know of. 0,0,0 will remain in the same spot regardless of the gizmo tool making changes. The original axis x,y,z will always remain the same, even when using geo-locate. keep this in mind when you are adding your model and setting the geo-loc coords. What you could do is set the heading by rotating the model in sketchup. Y axis (green) is default north in sketchup. I use this as true north and rotate from that. But I used DAE more-over KMZ

It took a lot of back and forth between MCX and FSX to make the necessary alignment adjustments, which is very unfortunate and time consuming. I really wish this was a direct 1:1 correlation.
Click to expand...
This is to help hone your skills. repetition repetition repetition

It was nice placing the signs in their exact spot in Sketchup, and having them grouped into a single file, but the inaccuracy between Sketchup and FSX results in too much time fine tuning the alignment. So now I'm wondering if exporting the individual signs, converting to MDLs, then compiling a BGL with location information in XML for each sign will be more accurate, and take less time?
Click to expand...
Do you have a screenshot to show what you mean?
I have large collections of objects done this way at had no placement or heading issues. I exported to collada and used mcx to convert and place.



There is also the option of exporting to MDL, creating a Library, then placing with ADE or other apps.
So many different options/workflows! And what works best for placing a single item is not always the best for placing 40+ items.
Click to expand...
All the better to serve the masses with


Oh yeah... if you do place several items over a long distance in a single Sketchup file ... dont forget to correct for FSX Earth curvature! ;)
Click to expand...
MCX has a feature for this
 
Thanks for the follow up guys. I finally got some time to get back into the modeling so I decided to retest this issue.
Test steps:
- created a fresh Sketchup file;
- geo-located the file and grabbed the photo region for the area;
- created a polygon, tracing over the runway as seen in the photo-background;
- textured the poly;
- exported to DAE and imported into MCX
- Used the Ground Polygon Wizard (didn't do this last time since they were objects)
- set the co-ordinates to match what was used to in Sketchup (axes origin) and ran the wizard, leaving heading to 0.

I imported into FSX and got the result below. The runway texture is not complete, so ignore that. Note, the heading difference between Sketchup and MCX/FSX. I will have to change the heading in MCX to correct for this, just as I did for my taxi signs.

For a second, I trusted Sketchup and questioned if the stock runway/airport heading was wrong, but then I noticed my photo ground texture which was made from GeoTiff and matches stock. So I feel the issue is in Sketchup's Geo-location/photo background feature. I havent tweaked the heading in MCX yet, but I'd be willing to bet that it will be the same difference as was needed for the taxi signs.
 

Attachments

  • Rwy22_Test.jpg
    Rwy22_Test.jpg
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Hi,

I just did a quick test. I grabbed a photo with an airport in SketchUp and drew the runway. But when I export it to KMZ and import in ModelConverterX there is not only a latitude and longitude specified, but also a heading. So it seems SketchUp already specifies the heading offset for you.

Maybe you better use KMZ instead of DAE, since that will keep the position information.
 
When I did the taxi signs, I tried both DAE and KMZ. I did notice the KMZ provided the location and heading, but the heading was still off once the model was in FSX. It was only off by 0.08 degrees, but when dealing with long-distance models, the tenth of a degree has an affect.

I will retest the runway using KMZ now and let you know if there is a difference.
 
Okay... So I exported as KMZ. MCX Ground Poly Wizard picked up the co-ordinates, but the heading was 0.00. Same result, misaligned. Using the same KMZ, I corrected the heading to 358.88, which was the same heading required for the taxi signs (different axes co-ordinate) and the runway alignment was perfect!

So at this point, it doesn't matter if I use DAE or KMZ, I have to set the heading in MCX to 358.88 (-1.12 degrees from 0.00) in order for my scenery to align in FSX.

It could be the photos Sketchup is pulling down for me when Geo-locating is off by 1.12 degrees. :confused:

Whatever it is, it at least appears to be consistent for the airport/area I'm currently working on.

Another work around may be for me to get satellite images from another source, aligning to the green axis in SKP to North, and then just keep track of axes origin and manually set the co-ords in MCX. /shrug

Airport is KAEG (35.152720, -106.791213) if anyone wants to do any further testing.
 
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