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makit3d
PostPosted: Sun Oct 10, 2010 1:04 am    Post subject: .BT importing Reply with quote



Joined: 10 Feb 2007
Posts: 123

Hello! It's been quite a long time since I posted here. I've been away from Grome for some time while the rest of life took over and pushed everything else aside.

However, I have been working with the program again and running into an problem that is killing me. It's late and I just can't focus on what should be a simple solution or answer.

I have a .BT file exported from Global Mapper. It's one of 9 that are 4096x4096. Measuring the terrain in GM I get a distance of approximately 86k from edge to edge (85.73k). In Grome I am trying to be sure I get as close to this as I can.

In 3ds Max I did what I have done before with my 4Kx4K maps. I created a box the size I wanted to use as reference and exported it out as a .DAE (Collada) file. Seems a bit odd, but it worked before quite well.

Here is the issue. Regardless of what settings I make with the .BT importer the two objects never match up. I assume it must be the exported box not importing correctly or was not exported correctly.

It may be that the file isn't actually 86k like I measured. I have observed that the imported 86k box seems to always be the same size in comparison to the terrain. I don't see an option anywhere to make this happen so I am somewhat lost.

Is this something simple that my tired mind will figure out when I get some sleep? I hope so. Help would be appreciated my friends.
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ALicu
PostPosted: Sun Oct 10, 2010 8:21 am    Post subject: Reply with quote



Joined: 12 Feb 2007
Posts: 1326

Hi,

Basically if your BT zone has 85730 meters on an edge, you need to use the proper tile size in BT importer, which would be 4095 (you have 4096 points in the BT so you have 4096-1 tiles) divided by 85730 = 20.9353 units per tile.

While exporting the collada file make sure you are using the proper internal units of 3DS Max (exported files are in the internal units no matter what external units are shown in the UI).

When you said that the imported box don't match are you referring to the fact that the collada box is not matching in size the imported terrain?

Can you send me the files via email? Please send the collada file and the bt file.

Regards,
Adrian L.
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makit3d
PostPosted: Sun Oct 10, 2010 10:18 am    Post subject: Reply with quote



Joined: 10 Feb 2007
Posts: 123

I will send them in a few hours (after work). My numbers were close to what you posted so it must be in the 3ds file. Units were set to Metric, but perhaps I missed something. Thanks!
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Hyperg
PostPosted: Wed Oct 13, 2010 12:35 pm    Post subject: Reply with quote



Joined: 12 Feb 2007
Posts: 20

Hello,

I've checked the .DAE file from your mail and it seems to have been exported with INCH unit setup:

Code:

<?xml version="1.0" encoding="utf-8"?>
<COLLADA xmlns="http://www.collada.org/2005/11/COLLADASchema" version="1.4.1">
  <asset>
    <contributor>
      <author>Gawdly Won</author>
      <authoring_tool>3dsMax 9 - Feeling ColladaMax v3.05B.</authoring_tool>
    </contributor>
    <created>2010-10-10T18:08:07Z</created>
    <modified>2010-10-10T18:08:09Z</modified>
    <unit meter="0.0254" name="inch"/>
    <up_axis>Z_UP</up_axis>
  </asset>



This yields rather large values in the vertex coordinates which Grome interprets as default unit values when you load the box (default unit is meters). In other words, the box was very big inside the Grome scene.

I've re-exported the box, using meter as internal units (which is usually our default unit when working with 3dsmax) and also used 21 meters as tile size when importing the BT file (21m ~= 86km / 4095 tiles) and they seem to fit perfectly:



We plan to add a more consistent unit system in Grome aswell (the Georeference support is working on a "conventional" level - nothing is transformed, only interpreted). For now, if you don't wanna change your 3dsmax unit setup, you can use the object transformation tool to adjust the units of the objects when you import them in Grome. In the case of the inch-units box, you can scale it down to 2.54% which represents the unit conversion between meter and inch (the conversion value is actually displayed in the COLLADA xml file - as you can see in the code paragraph above, at "meter=value" attribute in the "unit" tag).

I hope this helps you to solve any possible problems with units.

Regards,
Razvan D.
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makit3d
PostPosted: Wed Oct 13, 2010 3:32 pm    Post subject: Reply with quote



Joined: 10 Feb 2007
Posts: 123

With what you posted it would seem my problem is not solved and it is on my end that it has the problem. My 3ds max units were set to Metric after I realized the problem. However, the problem of the export still existed. Perhaps a new file should have been started with the new units instead of re-using the old?

I also used Silo which has been set up from the beginning and never changed to use metric units. The .DAE file was actually exported from Silo as a .OBJ file, imported into 3ds Max, checked for the correct units and then exported as a Collada file.

Previously it was straight from 3ds Max that the .DAE file was exported with both inch and metric units (metric, as I mentioned, after noticing my error).

I will double check everything to determine where my software is incorrectly set up.

Note: Just checked the .DAE file myself and sure enough the damn thing is set for inches. Checking Silo and 3ds Max they are both metric so it has to be in the exporting. I'll post an update if I find the problem.


On a completely different subject I also sent in an email (almost sent two email) about Grome 1 crashing. The problem was in the UDK exporter which obviously doesn't work with Grome 1. Sad
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Hyperg
PostPosted: Wed Oct 13, 2010 4:21 pm    Post subject: Reply with quote



Joined: 12 Feb 2007
Posts: 20

Note that there's a confusion spot (actually, once you've understood the 3dsmax units idea, it's quite straighforward) concerning the units setup in 3dsmax. The opening dialog window from the Units Setup has little to do with the internal values stored by 3dsmax for the vertex coordinates. I'm talking abt the units window with the Metric/US/Custom/Generic radio buttons. Those are DISPLAY UNITS, which can be anything the user wants, and they are used to convey the internal values of a length and coordinates into something that the user is more accustomed to. You can setup your own "Coffee Mug" unit to be 10 Centimeters long and 3dsmax will display CoffeeMugs allover the place. The actual units convention used for the values of the vertices are inside the SYSTEM UNITS setup window which can be opened from the button on the top of the Display Units setup.

The display units are only means to convert between the internal units and what is shown in the user interface. Usually, setting the display units to "Generic" will show the actual internal values of the coordinates / lenghts, etc.

Small recap of how things work, with one possible scenario for the inch issue:

System unit = 1 Inch;
Display unit = Metric -> 1 Meter;
3dsMax displays Meters in every spinner for lenghts and point coordinates.

You create a box with keyboard entry, each side having a length of 87000 units (which will be displayed as meters, in the user interface). All the measurements you perform on the box will show 87Km.

BUT, internally, 3dsmax creates a box with vertices containing numeric values somewhere around 3425197 because thats how many inches are in 87Km.

Not sure about starting a new file with new coordinates, i think 3dsmax will ask you if you want to convert the scene, if you modify the system units (i will verify this tomorrow when i'm back in the office). However, no matter what unit system is used, some help comes from the Collada format itself which contains the unit transformation ratio. If you're unsure about the unit system, just take a peek at the Collada units tag and scale the box with the unit-to-meter ratio, to bring it to the meter unit system.

Maybe this sheds some light on the units and setups issue, which i agree that it can get confusing at times, even more when working with several software packages along the way.
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makit3d
PostPosted: Thu Oct 14, 2010 9:13 pm    Post subject: Reply with quote



Joined: 10 Feb 2007
Posts: 123

I had no idea. Smile All these years I've used it was mostly for architectural work in the U.S.A. Having units set in 'inches' was just fine and I never really had to worry about exporting in anything but that until now.

Strange that it worked before so I must have known about it a year or more ago when I first starting using Grome.

Thank you very much for your help. As always the Quadsoftware team went out of their way to help my project and I am grateful.

EDIT: Ha! I just realized how utterly simple that was! Of course I knew it was there, but I haven't had to use it for so long I forgot it existed! There is an old saying that goes something like this: I couldn't find my ass if my hands were attached to it.

Some days that saying fits me very well.
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Hyperg
PostPosted: Fri Oct 15, 2010 6:30 am    Post subject: Reply with quote



Joined: 12 Feb 2007
Posts: 20

I'm glad we could help Smile

Like I said, the unit systems idea is rather simple to grasp, yet it makes for a pretty big percentage of 3d packages interchange tutorials, probably because, the placement of the display unit setup might seem a bit awkward, in the sense that it precedes the actual system unit setup in the user interaction flow and that causes the confusion.
On the other hand, the user really wants to setup the way the software interacts with him, rather than tweaking the internal configuration, but still he needs to be aware of how things work, especially if the assets are expected to travel through several editing steps in different editing packages.
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