[Plugin] OBJexporter v3.0 20130131

Ben Ritter

TIG, thank you again.

IdahoJ

@jolran
Just use blender.

Or Meshlab. http://meshlab.sourceforge.net/ I use this a lot to post process exported .obj files and it works very well. Works on cleaning up manifolds and inner faces as well. Very powerful application. Free too ...

Cheers

wongfoon

Great work! I have been looking for something similar for a long time.

wongfoon

It works well in most cases. However there seems to be some problem with flipped (mirrored) objects. Half of the object will be black, maybe due to incorrect normals. Try this model http://sketchup.google.com/3dwarehouse/details?mid=dd9ece07d4bc696c2bafe808edd44356&prevstart=0 and you'll see how.

TIG

Indeed the SKP is made from two mirrored halves as component-instances.
Somehow one mirrored version seems to flip the exported faces.
The SKP does have some issues with faces reverse - like the windows - but even with those fixed it messes up...
If you explode the parts and export it's all OK...
I'll investigate - an instance's transformation SHOULD be properly transferred to any exported faces, obviously it's failing here...
However, note this... if I export the OBJ to Octane [that should be using the very same OBJexporter algorithms and code (I wrote both!)] then it renders OK with the two parts intact OR exploded.
Only when it's reimported into a SKP does it mess up... However, the Octane OBJ reimported into a SKP displays no flipped face issues either because the materials are on the backs of one half! - just weirder and weirder...

wongfoon

I am really thankful to your kind and timely response. Similar problems are found with several models downloaded from the warehouse. At this moment I'll try to explode them before exporting, as instructed. So keep up your excellent work!

TIG

I have found that if a component is 'flipped' the triangulated face loops in the OBJ are returned clockwise rather than counterclockwise, while the vertex normals remain correct.
Some apps like Octane [and even my olde OBJimporter] ignore this issue and import it as expected, BUT others like the Fluid-OBJimporter and some other MeshLab type app's baulk at this and make the face 'reversed' with the material on its 'back' so you see 'black' ...
I need to think of a way to see if an instance is mirrored and then reverse the order of the face's vertices to be ccw...

TIG

Here's v1.8 http://forums.sketchucation.com/viewtopic.php?p=294844#p294844
Fixed the recently reported issues with flipped-instance having reversed face vertices.
Now any mirrored/flipped instances should have their exported faces' vertices correctly ordered [ccwise]...
Although it's probably safest to explode any mirrored instances if you can, as some apps might still be flaky...

Fixed up x-wing SKP

Renderer OBJexport [with mirroring correction]

TIG

NOTE: After further testing v1.8 also has issues... so stick with v1.7 till another update is ready !

wongfoon

Is it possible to do this internally within the plugin, to explode and then undo explosion after exporting, as an quick & dirty fix Hopefully doing so might also fix some other potential tricky issues.

TIG

Here's v1.9 http://forums.sketchucation.com/viewtopic.php?p=294844#p294844
Completely has been recoded.
Issues with mirrored-instance's faces being reversed is now fully fixed.

IdahoJ

TIG, thanks a million for the updates! I've been using this plugin quite a bit and it's a real time saver for me ...

Cheers.

TIG

Here's v2.0 http://forums.sketchucation.com/viewtopic.php?p=294844#p294844
The tolerance checks for deciding if it's a 'distorted texture' have been further improved...

gzotti

Hi!

First, thank you for this superb OBJ exporter! I have previously used V1.6 for a large model (about 450.000 triangles mostly from a terrain TIN, counted by Meshlab), which took about an hour to export. The result looked perfect in Meshlab. All other OBJ exporters I tried including the Pro failed on that, so I warmly recommend yours. However, the V2.0 is not finished on the same model after 4 hours. (Win7pro, Core2duo, SU8pro uses 1GB RAM, lots of RAM free.) Was there any big change in the algorithm that causes this? Is it possible to find and try V1.7..1.9?

Kind regards,
Georg

TIG

The issue is that any 'mirrored' groups/instances don't export properly with the old versions.
The new version obviously has to do more work to ensure that the nested faces' orientation/UVmapping are now sorted properly in the OBJ code, so it takes longer to complete: unfortunately with Sketchup the processing time gets 'exponentially' longer the more entities there are to be considered - a small file might only takes a second or two longer to complete, but a much larger file WILL take a lot longer to finish...
One way to speed up processing would be to work on a copy SKP, and explode all groups/components before exporting the geometry? Then there'd be nothing to check/explode/heal etc, and therefore less to slow it down...

Here's a copy of the now superseded v1.8 [very similar to v1.6] IF you'd prefer to use that - it IS faster than more recent versions BUT it will give a flawed result with many third-party apps importing the OBJ, IF you have any mirrored instances... You choose...OBJexporter_18.rb

BigOto

Hi, this is BigOto2 from YouTube and other places. I'm just here to say this plug-in has been absolutely revolutionary when it comes to modding and creating new tracks for Mario Kart Wii. Me and many others in our community use it to design tracks in Sketchup and then convert them to the model format Mario Kart Wii uses (which requires OBJ). If you want to see any of the tracks created by us just search YouTube for "Mario Kart Wii Custom Track" or something like that. Keep up the great work!

TIG

Here's v2.1 http://forums.sketchucation.com/viewtopic.php?p=294844#p294844
Further work on avoiding the glitches with some flipped-instances' face-reversal/orientation/UVmapping.
Slight speed improvement over v2.0...

gzotti

Thanks a lot for 1.8 (for my large model) and explaining the differences. 2.0 finally came to an end, after about 6 hours. The model is technically simple enough to hope 1.8 will do.

I tried the 2.1 export on a different, quite complex model with lots of layers and some hidden and, yes, mirrored instances. After a while, a message popup says (I try to translate from the German SU8pro): "By your last action visible geometric shapes were joined to existing geometric shapes on an invisible layer." The model behind the panel looked weird, with lots of missing faces. After closing the panel the export then continued. The message and in-between appearance imply an unwanted edit operation, so I don't dare saving the SKP afterwards. However, after the export, it seems OK again - is there any chance/danger that something is actually edited? On the other hand, the OBJ misses a few faces. The 2.0, which gives the same message, looks worse, with some duplicate and maybe inverted faces in addition to the missing ones, so 2.1 is better, but I am afraid still some work is open. Just to let you know. Again, splendid job, I was disappointed with the Pro export.

TIG

I see the issue - if you have some raw geometry that is hidden or ill-advisedly on an an OFF layer, then it can merge with ON stuff being exported in the next coding... I can fix this though...

TIG

Here's v2.2 http://forums.sketchucation.com/viewtopic.php?p=294844#p294844
Resolved the issue of raw geometry, either hidden or ill-advisedly placed on an off-layer [either within the model or inside groups/components] inadvertently merging with exported geometry.