Problem with Lod

[Naiman Broome]

I have made a model and its lod, but the lod that is made of some flat panels, when I upload they get decentered and stretched up to the limit of the box shape of the whole model , I have used reset Xform but it didn't help , how can I fix that?

 

[Beq Janus]

All LODs expand to have the same bounding box. In this case you can pad this out by place either a small triangle or (I think) a single vertex at the two opposite corners of the bounding box. this will stop the LOD stretching. This problem is common when people make a physics shape too

Edited June 23, 2021 by Beq Janus

[Naiman Broome]

Thats the solution I did, but I thought and hoped it was fixed by now .

[Beq Janus]

It's not "fixable" in the sense that as part of the upload process all mesh is squished into a cube that is 1x1x1. Once it gets rezzed in second life, the object has a scale and the mesh is expanded to fill that "scale" and at that point (depending on the download) the only LOD available might be your lower LOD so it has to always work with what it has. The actual upload could be adjusted to "do the right thing" but there's a few changes needed to get us to that place.

In theory, the uploader could take the scale of the LOD object into account when it does the "squishing", so if a LOD is 50% the width of the reference at the time of upload then it would be encoded to be 1x0.5x1, then when it gets inworld that would still work. But, at present, this would still have significant shortcomings because there is no spatial relationship between LODs required by the uploader (that is to say they do not have to be in the same location across the different collada files), so the behaviour would be entirely dependent on whether the geometry centre matched (which is highly unlikely).

This is a problem that could be addressed, it needs a long overdue project that supports the uploading of the pivot point (https://jira.secondlife.com/browse/BUG-37617) and more generally the individual origins of model in a scene. Once we have that then the ability to retain the scale of LODs relative to the reference (High LOD) could be implemented. Raising a feature request Jira at https://jira.secondlife.com would be a great way to get this on the radar. 

Note: The origins issue as per my comments on the Jira above, needs both viewer and server-side work to fix the physics alignment problems. After that the rest "should" be viewer work.

 

 

Edited June 23, 2021 by Beq Janus

[Quarrel Kukulcan]

8 hours ago, Beq Janus said:

In this case you can pad this out by place either a small triangle or (I think) a single vertex at the two opposite corners of the bounding box.

If I recall correctly, the importer strips unconnected vertices, with one exception: it'll keep the very first vertex listed in your export whether it's connected or not. I'd go with small triangles or a single corner-to-corner triangle if you have a material to spare to make it transparent.

[arton Rotaru]

1 hour ago, Quarrel Kukulcan said:

a single corner-to-corner triangle if you have a material to spare to make it transparent.

A degenerated triangle with zero face area will do as well. No need for an extra material and transparency.