On 3/9/2010 12:47 PM, Colin Knowles wrote: > Hi, > Currently we're using 3DS models (entire city's) with TGA imagery for > textures. At the initial run of the database in the viewer we build ive's of > all the models and associated LOD's - I'm guessing (in absence of our > developers who are on holiday) that we're using OSGConv to convert the models > to the ive format - my question is this: > When ive's are built for models does the input texture type determine the > compression of the final ive? The reason I ask is that for convenience we'd > like to move away from TGA imagery to TIFF or JPEG , but will this alter the > final size of the ive's and ultimately the performance of the rendering? > I'd appreciate any input here as in the absence of the programmers I need to > give an answer about this to our data suppliers ASAP. > Not to over simplify it but we've gone from dealing with 5,000 models to > 150,000 models in the last 12 months in our databases and need to optimise > the models as much as possible - I know that 3DS is not a particularly good > format for alot of optimising techniques but we use it from a 'ability to > resupply' to end users point of view. That said we also handle nearly all > common formats so if anyone has an idea on a better format which I can > justify the use of to the company that would be great.
I think the compression is chosen automatically by osgconv. There are two kind of compression you're maybe mixing up here. OSGConv can compress the texture data using the DXT/S3TC style compression method. This reduces the texture size both in memory (and on disk, when stored in a compatible way). The other is just on-disk compression (JPEG/TIFF) which does not affect the in-memory storage size at all. OSGConv's automatic compression option: http://www.openscenegraph.org/projects/osg/wiki/Support/UserGuides/osgconv osgconv --compressed cow.obj cow.ive (and the other --compressed-blah options) do the former -- conversion to a compressed texture image which is then stored as compressed data in the IVE. Did that make sense? -- Chris 'Xenon' Hanson, omo sanza lettere Xenon AlphaPixel.com PixelSense Landsat processing now available! http://www.alphapixel.com/demos/ "There is no Truth. There is only Perception. To Perceive is to Exist." - Xen _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
