Optical Optimization Options

Once you have the hang of making your linksets to create and texture your meshes with Mesh Studio, the next important thing to conquer is the almighty LI (land impact) and equally strengthen the LoDs by controlling how they degrade with custom LoDs.  Remember, LoD is level of detail that you see as you move away from the objects with your camera in Second Life.  You see less and less detail, optically, just as in real life, the further you are from something.

First line of defense is your Mesh Studio menu when generating your mesh.  Here is one tactic I use.

ONE.
I create my linkset and leave the default settings for use as the High LoD level.

TWO.
For the Medium LoD level, I select the Low Poly setting on the MS menu.

THREE.
Low LoD level can use the Low LoD setting on the MS menu.

FOUR.
For the Lowest LoD level, you can do one of two things.  Use Use LoD Above or set the Triangle Limit on the level to 0 (zero).  

FIVE.
Calculate with the Use LoD Above setting and then again with the Triangle Limit set to 0 (zero).  Check to see which gives you the lower LI and decide which you want to use.

The second line of defense is to create the lower LoD levels by modifying your linkset.  The above workflow will work in many cases.  I recommend trying it to have values to compare to this second method of working.

The first thing to remember is that you are simplifying your forms but trying to retain the general silhouette of your linkset.  Let's use my lampost as an example.

This lamp is 22 prims: spheres, cylinders, boxes.

Since the center is a single tapered cylinder, let's focus on the top and bottom parts of the lamp.

In addition to the prims that make up the top of the lamp, I have created two sets of colored prims by tinting the faces of some of the plywood prims.  One I will use for the glass casing around the lampflame and another for the metal encasing what will be textured as glass.  The rest of the prims are all in plywood and this constitutes another material for a total of three.  In 3D programs, these material faces are set up by selecting faces on the mesh and assigning materials; in Mesh Studio, we select faces on the prims and tint them with all faces having the same tint belonging to the same material.

Second Life chose not to change their Edit menu, so to access these materials on the uploaded mesh, we use Select Face.  Doing this on any face that was within one tinted group of faces selects all faces in the group even if they are on opposite ends of the mesh (think of having candles in a candelabra and all the candles have one material; selecting and texturing one candle, textures all the candles at the same time).

The bottom of the lamp is a series of cylinders and a cut sphere.

This linkset had the Object2JoinedMesh script added and the default settings were used to generate the High LoD level.  Remember to name your root prim.

I made a copy of this lamp linkset and renamed it to reflect I would use it for the Middle LoD level.  Now it's time to examine the prims and see what you can do to simplify, but keep the general shape of the lamp.

It is very important, if you have made materials, to make sure that there is at least one face left on a prim that bears the tint used for a material face, so in this case that would be the plywood (which would be abundant) and the blue and green.  On the left is the original and on the far right, you can see the prims I removed (they need to be unlinked so they are no longer part of the linkset) and then the remaining prims modified to adjust for the removal of these prims.

It's a bit of experimentation to find what works and/or what is acceptable.  Remember these will be seen from further away.  You can see what I removed from the bottom and how I adjusted the prims, but I could have chosen to try it differently.

On the next copy I make, I name the root for the Low LoD level for which it will be used.  I have removed more prims and begin simplifying to full tapered boxes, but always seek to maintain the general shape that will be seen as your camera moves further away.

Since this is an LoD which is implemented at a much further distance, I am not concerned with small spaces between prims, you really won't see it.

Again, simpler forms.  As long as they have a visual feel for the shape, it will read fine at distance.

Note: The LoD will push on the shape of the prim to its largest mass, so it can be tricky to make shapes match the more delicate they are.  Case in point is the final version of the lamp as follows...

I changed the central cylinder on the lampost to a tapered box (right hand prims in image).  Notice how the tapered box looks thinner than the cylinder.  In trying this out, thicker versions, with the box shape, spread out in mass more than what could be seen with the cylinder, thus making the change visibly too different to the eye.  This thinness kept a more loyal silhouette to the original lamp and that is the goal.

For this final LoD, I was trying to trim a much fat as possible (i.e.prims/faces).  Look carefully on the right hand side final version and you'll see there is still one part of the blue material face prims left (bottom of the green prim) to make sure that the number of faces are maintained throughout.

So each of these versions, the original and the three simplified versions is used to do the four DAE files that are used in the four LoD levels in the SL Uploader window.  I set physics to lowest.  When this lamp was uploaded to Second Life, it came in at 4 LI from 22 prims and very strong LoD.

Hopefully this gives you some information to start bringing in your meshes with lower LI and better LoD.

Happy Meshing!
~ele