Second Life – How to Lower ACI – A Script

One of the complications in 3D rendering is working out how to blend the objects with transparent parts. Think of windows and SL hair. Designers can reduce the complication by how they use alpha layers and blending. I’m not going to try to explain how to set stuff up because I have yet to get it figured out. But, I came across a handy workaround for things we already have.

I buy hair, dresses, and other things that use blending modes. Most are no-mod. But, the script below can be used to modify them.

In the beginning of the video, I am wearing Magika’s Dreamy as purchased. This is hair that in the Linden viewer has an ACI of 4,699. Using the script reduces the ACI by 702. That is a saving of 15±%. This is my first try, so I have no idea if this is typical, minimal, or a max. You may find that high ACI items benefit more.

There is some degradation in the appearance. When zoomed out, it is barely noticeable. Only when zoomed in can you see the difference. Personally, the 702 ACI saving is not worth the loss of appearance.

I am standing in front of a window. It is about 60% transparent. You can see the blending issues with the original hair. Magika’s hair doesn’t create odd blends with my Slink body as some brands do. So, I used the window.

Changing to Alpha Masking removes the blending artifacts. It also makes the hair less transparent and causes the loss of fine detail.

Here is the script from over on SLUniverse where Adeon Writer posted it. The script sets alpha blending to alpha masking. The script:

// Adeon Writer 6/2017 – See SLUniverse
// Drag into any object to change all alpha blended textures to alpha masking,
// using the cutoff value below. The script will delete itself afterward.
// to avoid the changes not saving, apply script when rezzed on ground

integer Cutoff = 127;

default{
   state_entry(){
   llSetLinkPrimitiveParams(LINK_SET, [PRIM_ALPHA_MODE,
   ALL_SIDES, PRIM_ALPHA_MODE_MASK, Cutoff]);
   llRemoveInventory(llGetScriptName());
   }
}

To use the script, select a hair on which to try the script. Make a copy. We have no easy way to know what type of blending or alphas the designer used. So, in each case, you will be experimenting. If it does not work well, you can toss the copy.

Rez the hair on the floor. I am assuming you have made the script already, so drag the script from inventory and drop it on the hair. The script will run and delete itself. The hair will have been changed from using Alpha Blending to Alpha Masking.

Lowering ACI

The video shows how the Magika’s hair Dreamy changes. The image is a composite of still images showing the same change. Examine the ends of the hair to see the significant changes.

2 thoughts on “Second Life – How to Lower ACI – A Script

  1. “I buy hair, dresses, and other things that use blending modes. Most are no-mod. But, the script below can be used to modify them.” – And how do you drop a script into a no-mod object?

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