Mesh upload issue changing land impacts

[Winter Penucca]

I made a set of 3 round pillows. They were all duplicated from the same first pillow. All I did was adjust the mesh a bit on each so they created an arrangement. I did NOT change the number of verts, faces, or lines. I uploaded the set of pillows with a chaise that they were created to go on. The chaise and pillow set uploaded fine. I did not want the pillows linked to the chaise, so when in SL I unlinked them. Each pillow had 1 land impact. Fine so far. I wanted to try a different texture on the pillows so I went back into blender, duplicated the set of 3 pillows, and changed the seaming and unwrapping of the mesh. I did not change the size of the mesh in any way. I uploaded just the pillows, the original 3 with the new 3. Of the 6 pillows, some were 1 impact, some 2 impact, and one was 3 land impact. So I tried uploading with the chaise. Same thing happened, only the pillows land impacts switched around, the pillow that was a 3 was now a 1, a pillow that was a 1 was now a 3,etc. I just do a very basic upload, letting SL figure the LOD’s. I’m stumped, each pillow is the same mesh size, so why the difference in land impact? Why do the land impacts change with different uploads? Is there any way to correct this?  My upload settings are below. Thank you for reading this.

[Drongle McMahon]

You haven't mentioned whether the different LI effects are due to different download weights or different physics weights. You can determine this after uploading the whole set by unlinking and using the More Info button. However, one possible  explanation could affect either of these weights. The default LOD generator is non-deterministic. That is to say it can produce different results each time it is run on the same input data. This means you can get different low LOD meshes and thus different download weights. Now the default, convex-hull-type, physics shape is made by default from the convex hull of the low LOD mesh. If you specify a physics mesh, either by choosing one of the LOD meshes, or by a new file, then it will be the convex hull of that mesh. It looks like you have specified the lowest LOD mesh. Then the default convex-hull-type shape may be different when the LOD generator generates different results each time for that lowest LOD mesh. The same may be true for the prim-type shape generated after you click the Analyze button. You might be able to see differences in physics shapes by using the Develop->Show Metadata->Physics Shapes menu).

The solution to this problem (and some others), is to make your own meshes for the lower LODs and physics. The optimal meshes for LOD and physics are rarely the same. At the moment, the important thing for LOD and physics files for multi-object models is that the corresponding objects in each file are in the same order, as the uploader uses the order to decide which mesh goes with which in the LOD/physics files. In Blender, you can assure this by using a naming scheme that keeps the right alphabetical order, and checking the Sort-by-Object-Name option in the Collada exporter.

(In the Project-Importer development viewer, there is a more demanding naming convention, which may or may not find its way into the regular viewer).

[Chic Aeon]

Whilel Drongle's answer is (of course) correct!    I suggest that it could possibly be "over your head" a bit? It certainly was the first time he suggest that answer to me.

 

If that is so, here is a simpler idea. Upload the pillows individually. Yes, I know, it cost more that way. But you do have much more control and you can go over to the beta grid and experiment and TEST what to do with the uploader choices (change your LOD settings in your viewer and cam out and see what folks will SEE). Even if you don't make your own custom LODs, figuring out what a "good number" is for the automatic uploader is an necessary skill to learn.  It is importnat to understand that the default upload choices are RARELY the correct ones for your project. Only testing and experimentation will give you a handle on this.

 

And making your own LODs for the lower setting is a "good" thing. However, lots of folks do not do that and still come away with very good and useful mesh .   So little by little our skills improve, and don't get discouraged; just keep working. Blender is a harsh mistress! 

 

Most pillows unless they are bizarrely complex (ruffles et al) should be .5 or 1 land impact. You can use a simple cube for the physics model (just upload that cube.dae file AS your physics model choice) so physics will not be an issue, only download.

 

Those are hefty numbers in the upload window so I suggest that your mesh may be too dense for an SL type virtual world. Maybe getting rid of a little detail would help. The subsurf modifier often shown in tutorials is NOT your friend in SL. :matte-motes-sunglasses-2:

 

 

[Winter Penucca]

Thank you Drongle and Chic. Without this help along the way I would never be able to figure out all this on my own. Your answers are very much appreciated.

I am really struggling with the lower LOD’s. I’ve tried making my own a few times and did not get good results, so I guess that’s my next project to work on. With this help I’ll go back into blender better armed for the fight. (I probably should have mentioned the above upload windows were for a chaise, throw, and pillows. Individually uploaded the pillows are 1 LI.) I just could not figure out why each time I uploaded the group it came out so different. Thanks again for the support, now its time for me to put it to practice, and more practice:cathappy:.

[Chic Aeon]

By the way in case you didn't know. You can look at an object in the build menu and click the very tiny "more info" link and it will TELL you which part of the uploader equasion was the culprit for getting the land impact so high. My guess would be the physics .