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PostPosted: 15 Mar 2014 15:49 
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Joined: 28 Mar 2011 03:35
Posts: 83
I'm sure all are aware of the latest craze to sweep through the Trainz world - creating authentic looking model railways including the backdrop of the room and baseboard edges/floor. This is done by using "giant" scale objects for items such as walls etc.

While my first passion is still the creation of prototype routes, doing a model railway offers a break away from the task of putting together a real world route.

Obviously to start off a model type project you just have one or two flat tiles and work the track plan on to that. Having had only limited success using basemaps (they become hidden as you raise the terrain) I wondered if there is a procedure in Transdem to import the actual model railway plan as painted textures on to just a flat baseboard, i.e. no DEM and no skewing for real world projection. I have tried doing it on a section of sea where ground level is 0m but of course Transdem skews the plan according to the world projection.


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PostPosted: 15 Mar 2014 18:40 
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Joined: 05 Jan 2011 16:45
Posts: 1463
Vern, if I understand you correctly you want to "fake" a map projection. Assume you accept the UTM coordinate system as an ordinary Cartesian system with units in meters (which it is), you only have to scale your pixels of the raster image to meters. You can do that either by creating your own World file or your own TransDEM .trf file. Both are similar as they are define affine transformations. An ESRI world file would be regarded as pre-georef in TransDEM, while the native .trf file is post-georef, obviously.

This is a sample .trf file:
Code:
Transformation=2DAffine+UTMZone+Aux
Punkt0.x=0.000000000000
Punkt0.y=0.000000000000
Punkt0_t.x=615857.000000000000
Punkt0_t.y=5942414.000000000000
Alpha=0.000000000000
Skalierung.x=80.000000000000
Skalierung.y=80.000000000000
Scherung=0.000000000000
UTMZone=32U
Groesse.x=96000.000000000000
Groesse.y=88000.000000000000
png=1


"Punkt0_t" is SW corner in UTM coordinates. Could be 0 in your case. "Skalierung" (scaling) is meters per pixel of your image. "Groesse" (size or dimension) is the total size of the associated image in meters. If present, indicated by "+Aux" in "Transformation", it will supersede any "Skalierung".


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PostPosted: 15 Mar 2014 19:16 
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Joined: 28 Mar 2011 03:35
Posts: 83
That sounds a bit complex for what I want to achieve is, that is take a model railway plan scaled to real world dimensions and paint it on a flat un-terraformed baseboard(s) with no distortion of the shape or proportions.

It's not so much the scaling or georeferencing of the plan that's the issue, for my first (aborted) attempt I devised a scheme using Google Earth ruler to measure out the distance and apply the co-ordinates to the model plan.

I wonder if another option would be to use a DEM on the equator with the model railway plan georefenced over water?

Once I've finished my current project I'll give what you suggest a try.


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PostPosted: 15 Mar 2014 20:33 
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Joined: 20 Nov 2012 01:41
Posts: 65
If you are not able to create a flat plane asset yourself in Blender or something, why not clone one of the 500 meter (or 1000 meter) 2D UTM tiles from one of your earlier exports from Transdem? That way you have a known flat asset in Trainz, either 500 meter or 1000 meter. While the clone is open for edit, put your model railroad plan on the tile's texture file. If 256x256 is too small, you can resize it to 512x512 or 1024x1024 or 2048x2048 (maybe even 4096x4096, but I don't guarantee it). You'd also need to scale your plan to fit the texture appropriately depending on the scale you are modeling in.

I'm sure you could do this for yourself only, with no plans to upload to the DLS. This wouldn't be a misuse of a TransDEM UTM tile, would it Roland?

Regards,

Andrew

Edit - Coincidentally, this thread on the Trainz forum has been started today on a very similar topic.


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PostPosted: 16 Mar 2014 15:54 
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Joined: 28 Mar 2011 03:35
Posts: 83
Don't UTM tiles act in the same way as basemaps though, i.e. they are a fixed object with the issues that causes trying to place other items on top, underneath or accidentally moving out of alignment? That's why I would prefer to have the plan painted on in conventional Transdem method.


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PostPosted: 16 Mar 2014 17:45 
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Joined: 05 Jan 2011 16:45
Posts: 1463
Yes, UTM tiles are regular Trainz objects. From TS2010 onward, TransDEM puts them into a separate layer, with the Trainz layer functionality at your disposal.

Regarding raster images, you will always need scaling to convert pixels to your model space units. In TransDEM, these units are metres. Coincidently, metres are also the units Trainz works with.

So, independent of any tool, you have do define the dimension of your model railway plan and the resulting layout. If your plan is H0 1:87 or N 1:160 use this as an additional scale factor.

What I did not consider yesterday, there is also this "diagonal corners" georef function in TransDEM, which comes quite handy here. If you only have a single raster image / track plan, set the SW corner to 0,0 but make sure the NE corner receives the proper size in metres. This way you won't need to write the .trf file yourself. (The coordinate system must be set to UTM/WGS84, to avoid geo transformation.)


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PostPosted: 17 Mar 2014 15:25 
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Joined: 28 Mar 2011 03:35
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Thanks Roland, will give that a try.


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