Hi,

I am downloading 3d warehouse SketchUp files (mostly v6). I want to standardize the file size/ polygon count so when I bring meshes into Iclone the meshes are approximately the same scale. I also want to avoid bringing big and detailed meshes into IC if I am not going to get really close up to them. I have to export COLLADA format files .dae from SketchUp so I can use them in the next step.

Then I use the open source MeshLab to import the .dae file to reduce the polygon count and usually the file size. I export this file as an Alias Wavefront Object .obj format file.
(Filters > Remeshing, simplification and construction > Quadratic Edge Collapse Detection)

Then I bring the .obj file into 3dxchange, export it as a .vns and open it in IC4.

This works OK for small SketchUp files less than 2 Megabytes. Over 2 Megabytes MeshLab crashes.

And I don't get any colors/textures when I export from MeshLab even if the file size is lessthan 2 Megabytes.

Has anyone have any experience with this or any ideas for me to try? I want to use files over 2M and keep the textures if possible.

Thanks

Hi ,
i took a quick look at meshlab and the problem is that the program does not deal with UV data, meaning that it does not do texturing, so the second you do the process of reducing polygons, you loose your texture data. That program was made for 3d scan data, which has dense point clouds. It was not made for convertion of other file formats. hope this helps you understand why you are having those issues.

Cheers,

Stuckon3d

PS: I guess i read it too fast, it looks like it does preserve texture coordinates after reduction. So if you are losing the textures in the saving process after conversion It could be something as simple as not having your textures in the same folder as the geometry itself. So when you try to import into exchange, it can not find the textures because they reside in a different folder. Try that and see if it works.






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I had a small 3ds file with a texture, I exported it and reimported it in MeshLab and it still had the texture, so it seems to handle textures. I am absolutely no expert, having just dowloaded and installed the program, but I saw some options that were related to textures.

You could try exporting as a 3ds file to see if your textures are preserved. I have had problems with obj files not keeping their texture. Sometimes it is simply a matter of the obj file not referencing the texture files correctly. You can open the obj file in a text editor and see if any textures are referenced.

EDIT: I experimented somewhat further and was able to import as 3ds and then export as obj. I imported the obj file in 3DXchange and it did include the texture.  I did a simple vertex reduction and I still had a texture. So it should all be possible with textures.

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Hey,

I just logged in to say a heartfelt thank you to you both. You actually downloaded MeshLab and looked in detail at my problem. That is amazing. Thanks stuckon3d. Thanks zuijlen.

I'll do some more experiments and will be back in a couple of days to report.

Cheers

PS I suspect part of my problem is the SketchUp format I am starting with. Some SketchUp meshes come into MeshLab with textures, others do not. My free version of SketchUp only exports either kmz or dae. My computer might also be a problem.

PPS I almost fell off the Open Source path and considered buying VizUp. But I'll play around with MeshLab's poly reduction for a few more days first. I also looked at Blender's poly reducer function.

In order to reduce poly counts, I use Polygon Cruncher Plugin inside 3ds Max and it does a pretty good job as you have control over several ways of reducing poly counts, plus save UVW and textures etc...

But there are no magical solutions. You will always be able to reduce 50% poly count with minimal side artifacts automatically. However, the best results are obtained by identifying the high poly count meshes, deleting them and redoing them in Max. These typically are either hidden, or are of generic shape so they are easy to remake with low poly counts, i.e. cones, cylinders, boxes etc. Most precisely if they originate from sketchup models.. I typically can reduce to 20% poly count by redoing the worse case meshes manually...

My grain of salt.

Hope this helps. 

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I have a further update.  If you search on Google for file size and MeshLab, I found some reports that large files may pose a problem under a 32-bit Windows OS.  As I have 64-bit Vista, I wanted to try this out.  I found a large (44 M) PLY file of a buddha and was able to load it succesfully. The vertix count was over 1 million. 

I have noticed though that MeshLab crashes easily if it doesn't like a file or when you do certain operations.

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Thanks zuijlen,

I have 32bit XP which may be the cause of my problems with MeshLab. Also thanks for your info about the obj format.

for a newbie the range of 3d formats is a bit bewildering at first.

I found a sketchUp to ASCII 3ds convertor - su2ase - which is a SketchUp plugin.
http://belgabor.vodhin.net/software/su2ase.zip
via
http://www.ataricommunity.com/forums/showthread.php?t=576789

On the atari forum page is a link to an app called Biturn that converts ase files to 3ds.
http://mirex.mypage.sk/index.php?selected=1

3dxchange then converts the 3ds file to a vns.

I'm probably not using Biturn properly but it is making the meshes nice and small - which is exactly what I need. (I understand that small is a relative term) There are no textures coming in with this method though.

I'll need to do more research on this. I think I'll look for polygon reduction in obj or dae files. I like working with text/xml I can read.

Thanks for all of your advice.