The issue of model centering in Sketchup prior to export was previously subject of an interesting discussion in this forum at:
Note that Dick Ludowise (aka "Rhumbaflappy") has generously provided a plugin Ruby script "Center_Group_Bottom
", to center models "on-ground" in Sketchup's 3D world.
AFAIK, normally when we import or create a model from scratch in Sketchup, it places a model in a "quadrant" OFF of, but aligned with the "Origin of Axes" for Sketchup's 3D world.
IIUC, if we use Dick's "Center_Group_Bottom
" plugin for Sketchup, we will automatically move a model's "Reference Point" (the term used for the central datum of a 3D model in FS) to the precise "Origin of Axes" for the Sketchup 3D world... while still maintaining the base level of the model on the "ground" plane
of the Sketchup 3D world.
If, however, one purposely wished to position a model in alignment with the precise "Origin of Axes" for the Sketchup 3D world AND
center the model on the vertical axis, so that half of its extent is located above the ground, and half of its extent is located below the ground, one could do so with Todd Burch's plugin "MoveToOriginAndCenter
" ...discussed here:
Again, note that Dick's "Center_Group_Bottom
" plugin does NOT
above and below ground... it instead simply keeps models on
That is probably a preferred workflow
, BTW, as once the model is imported and converted by ModelConverterX for use in FS, we would then simply adjust the Altitude relative to the local "ground" (using the default "AltitudeIsAGL-TRUE
" parameter setting) when placing the scenery object via XML.
However, in certain situations (such as when modeling objects with (very large / tall) terrain skirts intended to be placed onto sloped ground in FS scenery), we may wish to fully center the model on the "Origin of Axes" for the Sketchup 3D world with Todd Burch's plugin "MoveToOriginAndCenter
We would then be centering a model on both the horizontal axes and the vertical
axis, so that half of its extent is located above, and half of its extent is located below the ground.
If you load the model in ModelConverterX (aka "MCX") you can see where the reference point is. It is the center of the grid that is shown.
I don't think you can see where it is from SketchUp. When exporting the reference point usually ends up in the center of the entire scene.
I had not looked at this recently; and if I follow Arno's description above, the Sketchup export (or the ModelConverterX import) process may be 'automatically' centering the model on both the horizontal
axes ...with a result similar to what is done by manually
running Dick's "Center_Group_Bottom" plugin.
If indeed the ex
: ModelConverterX import process is 'automatically' centering the model on both the horizontal
axes, this may prevent users from maintaining a preferred positioning of models in a given location within the 3D world, and I'd be concerned about having an option to disable / over-ride this within ex
: ModelConverterX ASAP !
: In some cases, IMHO, users may wish to ex
: keep an object positioned so that its NW corner is actually at the NW corner of the model !
Also, for purposes of photo-realistic rendering of textures for a model, one may achieve lighting and shadowing more compatible with an intended "real world" placement location for a FS scenery object by manually aligning the model and its "N-S-E-W heading" with the matching image position on a ground tile imported to Sketchup via:
Sketchup Menu > File > Geo-location > Add Location...
When a model is properly positioned relative to the Geo-location image ground tile, one can set the Sketchup Sun position as desired for ones photo-realistic rendering utility etc.
Alternatively, for a model created "from scratch" in Sketchup, one can navigate
Sketchup Menu > Window > Model Info > Geo-Location > "Set Manual Location...
...and set the Geo-Location coordinates where the model is "intended" to be placed in the FS 3D world.
: AFAIK, ModelConverterX will not utilize any Geo-Location info unless the model is exported from Sketchup as a "*.KML
" format file package.
After all geometry and (ex: photo-realistic / rendered) texturing is finalized in Sketchup, one would then
use Dick's "Center_Group_Bottom
" plugin to place a model at the origin of the 3D world axes (but still on
the "ground") ...prior to import into MCX.
: The Sketchup 3D world X, Y, Z Axes are oriented in, and have these directions relative to the "ground":
Determining which way is up, - - -down, east, - - -west, north, and - - -south
...And how to "stay on axis" when modeling:
Ensuring edge alignment to axes
in Sketchup its where the 3 axis meet b4 starting the modification. as far as ive been able to perform it cant be changed even with the gizmo, the original point never moves.
: One can "temporarily" move and re-orient the Sketchup 3D world Axes to a position more helpful to one's "locally-off-the-default-3D-world-axis
" modeling process via:
Axes Tool: Moving the drawing axes
Just remember to change Sketchup 3D world Axes back to the default after working "locally" !!!
Axes Tool: Resetting the drawing axes
Hope this helps !