Difference between revisions of "Mega Prim"

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(Mega prims are NOT automatically made phantom when rezed.)
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== Building with Mega Prims ==
== Building with Mega Prims ==


When [[rez]]zed, mega prims are [[phantom]] by default. They can be edited like any other prim despite that it's not possible to edit their dimensions. The attempt to edit the dimension of a mega prim will result in all sides of the mega prim which are greater than 10m instantly switching back to the regular 10m limit. To be able to edit and move some huge mega prims, it is suggested to access the [[advanced menu]] (press ''CTRL-ALT-SHIFT-D'') and to toggle "Limit Select Distance" off, as well as "Disable Camera Constraints" on.  
Mega prims can be edited like any other prim despite that it's not possible to edit their dimensions. The attempt to edit the dimension of a mega prim will result in all sides of the mega prim which are greater than 10m instantly switching back to the regular 10m limit. To be able to edit and move some huge mega prims, it is suggested to access the [[advanced menu]] (press ''CTRL-ALT-SHIFT-D'') and to toggle "Limit Select Distance" off, as well as "Disable Camera Constraints" on.  


In order to support builders who'd like to use mega prims, Resident [[User:Zwagoth Klaar|Zwagoth Klaar]] collected and sorted these prims to release his so called ''Salt HUD'', which is a free tool and gives access to a huge database with mega prims in different dimensions.{{footnote|1=You can purchase the Salt HUD [http://xstreetsl.com/modules.php?name=Marketplace&file=item&ItemID=712605 here] for free.|2=You can purchase the Salt HUD here for free.}}
In order to support builders who'd like to use mega prims, Resident [[User:Zwagoth Klaar|Zwagoth Klaar]] collected and sorted these prims to release his so called ''Salt HUD'', which is a free tool and gives access to a huge database with mega prims in different dimensions.{{footnote|1=You can purchase the Salt HUD [http://xstreetsl.com/modules.php?name=Marketplace&file=item&ItemID=712605 here] for free.|2=You can purchase the Salt HUD here for free.}}


== Future of Mega Prims ==
== Future of Mega Prims ==

Revision as of 03:52, 11 November 2008

A mega prim (also referred to as megaprim, mega-prim or huge prim) is a primitive with at least one side beeing greater than 10m. Their creation is not possible due to limitations.

History

In 2006, Resident Gene Replacement managed to tweak the viewer in a way that allowed him to create these objects despite their limitations, until Linden Lab fixed the security hole some time later. The mega prims were distributed and spread quickly across the grid, since Residents found many ways to use them in their builds. While Linden Lab didn't ban the objects completly, their policy was to return them if they were a "nuisance". In a Town Hall discussion at December 20th 2006, Linden Lab announced that they were going to allow the use of mega prims on private estates[1]. After open sourcing the viewer, another bug exploit allowed the creation of mega prims for a limited time. Residents took the chance to create a variety of these objects in many different sizes, even those which covered multiple regions completely. Linden Lab announced and discussed plans on using methods to prohibit the use of mega prims greater than 256m in one dimension, but then decided to only limit them to 64.000m, since they found legitimate use for the 256m prims (for example in horizons and skies).[2]


Problems with Mega Prims

Problems with mega prims are obviously related to their huge size. They can reach far beyond parcel borders and therefor disturb neighbours with their presence. Residents might not even recognize that it is a mega prim which is hindering them, since they might be inside the mega prim and therefor won't be able to see it.

Non-phantom mega prims might also cause a problem for the havok physics engine, since - again because of their size - they might detect - and need to handle - way more collisions per prim than with regular prims and therefor cause lag. EDIT: this argument is not founded and it's actually totally wrong. Why ? Because mega prims are used to REPLACE many smaller prims in a build and the increase of collisions per prim is then compensated by the decrease in number of prims. Example: you use a 100x100x0.1 mega prim as a floor instead of 100 10x10x0.1 prims. Then when you walk on this floor, with your avatar the physics engine will detect the exact same number of collisions with the mega prim as with the 100 individual prims. The actual difference is that your 100 normal prims have each 6 faces which means the viewer and the physics engine on the sim server have 600 faces to deal with, while your mega prim got only 6 faces for the same floor. Also, the asset server, the sim server and the viewer have to deal with 100 different objects, each needing their parameters to be exchanged on the network and stored in database whereas the mega prim floor is one single object. FACT is that the mega prim floor LOWERS the lag A LOT instead of increasing it.

There are also reports that the graphics engine wouldn't be able to work well with prims larger than 256 meter in any dimension.[3]

Building with Mega Prims

Mega prims can be edited like any other prim despite that it's not possible to edit their dimensions. The attempt to edit the dimension of a mega prim will result in all sides of the mega prim which are greater than 10m instantly switching back to the regular 10m limit. To be able to edit and move some huge mega prims, it is suggested to access the advanced menu (press CTRL-ALT-SHIFT-D) and to toggle "Limit Select Distance" off, as well as "Disable Camera Constraints" on.

In order to support builders who'd like to use mega prims, Resident Zwagoth Klaar collected and sorted these prims to release his so called Salt HUD, which is a free tool and gives access to a huge database with mega prims in different dimensions.[4]

Future of Mega Prims

While Linden Lab is still not supporting or endorsing the use of mega prims, developer Andrew Linden talked about[5] future plans on what he called the "liberation" of mega prims. He is planning to

  1. Allow parcel owners/managers to move (or maybe just return) objects that overlap their parcels.
  2. Provide UI feedback to the Resident when moving their objects, indicating whether they overlap neighboring parcels.
  3. Maybe provide real-time enforcement of parcel permissions. That is, allow parcel owners to set a paranoid bit “I don’t want anyone, or these specific people, from putting stuff on my parcel”

He noted that "once that is done then perhaps we will allow you to make prims/objects as large as you want as long as they fit on your parcel."


References

  1. ^ Linden Lab allows use of mega prims on private estates (see at [14:55])
  2. ^ Linden Lab doesn't ban 256m mega prims.
  3. ^ The big prim problem - Bugs with mega prims
  4. ^ You can purchase the Salt HUD here for free.
  5. ^ Read the 2008-04-09 and 2007-12-21 transcripts of Andrew Lindens Q&A sessions about the havok4 engine