[Plugin] OBJexporter v3.0 20130131

bomastudio · 18 Dec 2012, 16:12

Well I need to bypass the Octane exporter (as I use Ubuntu/Lubuntu+wine+SkecthUp) and the webdialogs doesn't work no more (with SU6 webdialog worked....). So exporting in OBJ format I can solve model+texture troubles, but I need to export also the scenes (cameras).

TIG · 18 Dec 2012, 16:22

So this is an Octane based query... only peripheral to Sketchup.
There are already two tools available on the Octane Sketchup forum for licensed users.
You need 'OctaneOCMbatchExporter.rb' - the tools allow you to batch-export your scenes' cameras and suns/shadows settings into Octane OCM files, which can then be loaded and used as 'nodes' in the matching OCS file, that you have made from the SKP exporter via OBJ/MTL files etc.
That forum's thread is named "Batch Cameras / Suns OCM Exporter v1.0"

bomastudio · 18 Dec 2012, 18:01

TIG, you are definitively the best source of info about SU!!!! thanx, how would I do without you?

eubz · 25 Dec 2012, 04:31

nice. i love this exporter.

sceptile · 12 Jan 2013, 22:23

says the file can amage my computer?

TIG · 12 Jan 2013, 23:26

@sceptile said:

says the file can amage my computer?
Let us assume you mean 'damage'...
Who, what where, when, why and how ?
Yours might win this week's prize for the most useless error report / query...

sceptile · 13 Jan 2013, 07:27

and i cant find the plug in folder i have sketchup 8 free where is it? thanks

TIG · 13 Jan 2013, 10:29

@sceptile said:

and i cant find the plug in folder i have sketchup 8 free where is it? thanks
Your questions get little clearer, and also show that maybe you aren't yet ready for using scripts...
There are extensive Sketchup Help files available to you.
For example under the Sketchup main menus Help > Learn About Plugins... opens a link which tells you exactly how to install Plugins etc...

Also you have not yet explained the '[d]amage' statement that you made earlier...

TIG · 13 Jan 2013, 10:29

@tig said:

@sceptile said:

and i cant find the plug in folder i have sketchup 8 free where is it? thanks
Your questions get little clearer, and also show that maybe you aren't yet ready for using scripts...
There are extensive Sketchup Help files available to you.
For example under the Sketchup main menus Help > Learn About Plugins... opens a link which tells you exactly how to install Plugins etc... Giving the full paths for PC and MAC,

Also you have not yet explained the '[d]amage' statement that you made earlier...

Sound · 25 Jan 2013, 18:50

Hello TIG, thank you for writing such an useful plugin. I look forward for using it in a 3D printing workflow but I noticed two problems - the first one being more serious.

Draw a cube and export it as OBJ. It contains 16 triangle facets, but I would expect 12. If you inspect the generated OBJ you'll notice that it generated a tetrahedron inside the cube by triangulating the internal space. Hence the four more facets. I think this problem needs to be addressed. What do you think about it?
Resulting OBJ files contain lots of duplicate vertices. I think this is because you don't reuse vertices but you generate new ones all time. However this corrupts the topology of the generated OBJ file. If you open it with, say, Netfabb Studio Basic (a popular free utility for 3D printing) it will report all faces as unconnected. I don't know whether SketchUp API associates a unique ID with each vertex; in case it doesn't I think you could just build your own dictionary based on coordinates and check whether you already wrote that vertex and if so, just reuse its index when defining the new facet.

Thank you for your work, and I really hope you can fix these two things.

TIG · 25 Jan 2013, 20:43

@Sound

I am afraid you are mistaken.
I have tested this extensively and a cube of 6 faces exports as a cube of 12 facets, because they are each triangulated.
You can clearly see it in the OBJ code.
If I import the OBJ it then arrives with 12 triangulated faces too.
this occurs with many OBJ importing apps.

IF you triangulate the faces manually before exporting you can create internal 'partitions' inside the cube depending on the order the diagonals are drawn, this should only make more that the visible 12 faces

So this suggests there is something wrong with your initial cube if it indeed has 16 facets when exported, or alternatively something wrong with the app into which you are importing it? There are many apps that import these OBJ files quite acceptably without new facets or complaints about unconnected facets...
What are you using to import it ?

The code takes faces in the same context using the same material, triangulates them as necessary and produces the facets to suit. This tool is used as the basis of several rendering apps. The Pro OBJ exporter exports a simple cube with a file that is all but identical to this tool's file, so I don't think there's anything wrong with it...

Try the Pro version OBJ exporter and see it's the same...

I suspect you are either mis-modeling the cube beforehand OR not using appropriate import settings and getting spurious results... I suggest you make an OBJ made from a 1m cube in the positive quadrant of the axes, bb.min at [0,0,0]. Then compare it with mine in the ZIP, which only has 12 facets...

obj.zip

Sound · 26 Jan 2013, 10:54

Thank you for the answer. Yes, it looks like those internal faces were already in SketchUp. A new test shows 12 facets, and that's fine.

Still, the other problem persists. Even when the exported cube results in 12 facets, the file contains 24 vertices (you can check this by opening the OBJ file with Meshlab or any other importer, or even by counting the "v" lines in the OBJ file). This looks very wrong, as the original geometry only has 8 vertices. Can you help me about this issue too? Thanks!

TIG · 26 Jan 2013, 12:04

So no apology for putting me to unpaid trouble when it was entirely your error?
My exporter does work differently from the pro-OBJexporter, which minimizes the number of vertices by recycling them when possible.
However, my version treats each context, material and face as a separate set, and doesn't reused vertices. The coding is such that it would be very awkward to effect...
However, it has no noticeable effect on the resulting form and a ood 3rd party app should be able to cope with welding vertices etc anyway...
Get Pro if you really do NEED this functionality, and are not just being 'anally retentive'.
After all my tool is 'free' [donationware] and you cannot readily expect, let alone demand, changes to its functions...

Sound · 26 Jan 2013, 14:55

Well, I'm just reporting a bug. A cube, having 8 vertices, is exported with 24 vertices
This is a wrong representation of the object and has a very noticeable impact on all uses of the OBJ file when topologic integrity is required (3D printing is one example).

Of course I expect nothing from you, being it freeware. Whether you want to fix this bug or leave it there is entirely up to you.

TIG · 27 Jan 2013, 12:46

@Sound

The vertex 'duplication' isn't actually a 'bug', since that would suggest that it isn't doing what it is intended to do: and it currently does exactly what it is coded to do.
However, I do take your [inelegantly put] point that vertex entries could be 'reused' if they are 'shared' by more that one facet...

So I now have an idea on to make an adjusted version of the code that will now does this: and it can also have a few other tweaks; to reduce the file size further, to optimize the processing time etc.

I'll post it soonest...

PS: Although I do 'reserve all rights' to my code... please feel free to make your own improvements to any of my tools, and either PM me or post them here, of course for free unfettered use by all members... The only thing I ask is not to post whole scripts in the same thread as it'll cause confusion...

TIG · 27 Jan 2013, 12:54

Here's v2.8 http://sketchucation.com/forums/viewtopic.php?p=294844#p294844
The D.P. accuracy is not now applied to 'whole numbers', and any -0 values becomes 0.
Any shared-vertex entries are now 'reused'.
The OBJ file size is minimized and the processing time is optimized.

Sound · 27 Jan 2013, 14:36

TIG, thank you very much for working on that and for clarifying your terms about modifying the script.
I will test the new version as soon as possible and report success or failure.
Have a good day.

Sound · 28 Jan 2013, 15:44

I can confirm this works for any model I tried.
Thank you! Exported OBJ is now topologically correct and thus suitable for a lot more uses.

TIG · 28 Jan 2013, 15:49

Good.

TIG · 30 Jan 2013, 17:00

Here's v2.9 http://sketchucation.com/forums/viewtopic.php?p=294844#p294844
Merging of shared vertices is now optional, as it slows down processing for larger models considerably; and it is only required by some more picky mesh-apps, but renderers etc don't seem to mind non-merged vertex data at all.