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Notes on Model Import
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DrJim
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Default Notes on Model Import - 05-02-2008, 11:10 AM

These are some notes I put together regarding model input into Alice. They are not really for beginning users, nor do they have much to do with OOP. Make sure you want to invest the time in learning this “non-programming” skill before you start. (The payoff is that Alice gives you one of the most flexible ways to statically or dynamically display the imported models in a nicely lit, 3D scene that I’ve found. )

The initial .3ds format model (in the .zip folder) was downloaded from http://archive3d.net/?category=28&page=1 and converted to .ase format in Biturn (a process described elsewhere in the forum). This particular model was constructed with many parts, each with it’s own material properties, but with no overall bitmap texture. One basic problem with this type model is that the material properties do not import well into Alice – but some, such as opacity, do come in. More on this in a couple of paragraphs.

The first problem was that importing the initial .ase model into Alice gave a real error (not just a warning, which is common). Looking at the details of the error showed that something in the model didn’t have a name – another typical error at this stage include illegal characters in a name. Relatively speaking, these errors aren’t too hard to fix, since the .ase file is a text file. In this case, a search for occurrences of “_NAME” in the file did find two places with a null name (“”). I named these two objects and then did another search for the null (“”) to make sure I had found everything – then saved the corrected .ase text file.

In this case, the .ase file (also in the .zip folder) now loaded fine. In the cases where it doesn’t, you just need to look at the details of the next error and decide whether or not it’s worth continuing. With the file loaded, the second challenge becomes obvious – there is a lot of detail here, the names are not very descriptive and most of the file material information did not import. One thing not immediately obvious – but apparent when you start moving components – is that all surfaces are only one sided. If you look at the back side of something, it is transparent.

The one-sided surface problem doesn’t appear to be bad here. If it is, the best approach IMO is to just abandon the whole effort. (If someone does have a way to import two-sided surfaces, please post it.)

The next step is pretty much brute force retexturing – I’ve only started it in the attached world. My approach is to click on various key objects – color them to make sure you know exactly what you have selected – then rename the parts with meaningful names. This may take an hour or so – but it’s much faster than developing an equivalent model from scratch.

With as many parts as the example model, you may also want to just delete parts that aren’t really needed in your application (such as the inside parts such as the seats if you make the glass opaque - note the transparency for the glass did import). This will put less of a strain on your computer when you actually run the world. Do look at the model from a variety of angles with the “excess” parts set to not showing before actually deleting them, however.
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File Type: a2w Car_Nissian.a2w (2.17 MB, 188 views)
File Type: zip Nissian.zip (1,022.6 KB, 170 views)

Last edited by DrJim; 05-02-2008 at 11:16 AM.
   
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