Mesh/FAQ

==General questions ==
===Are the existing content tools in the Viewer going away?===
Absolutely not! As with flexiprims and sculpties, meshes are part of the growing set of building tools available in SL. Our goal is always to expand the capability to create compelling experiences in SL. By adding new options like meshes to our builders' tool sets, we're enabling the next generation of content creation while still supporting the classic tools that have existed.
===What does a mesh model look like with a viewer that doesn't support mesh?===
Here is a scene filled with mesh objects, as rendered by the SL Viewer:
Here is the same scene, as rendered by a viewer that does not support mesh:
===How are meshes stored in SL?===
Meshes are stored the same way as all other Second Life assets (textures, scripts, etc.). The mesh asset data is stored as a custom mesh format based on gzip and LLSD.
== Modeling questions ==
=== What's the best tool to use to create a rigged mesh for Second Life? ===
This question is addressed in a forum thread, here.
=== Do you have some sample mesh content? ===
* Sample mesh files: Sample Content Page : Current list of Mesh files you can download and try out.
* Avatar mesh files: Second Life avatar meshes in .obj format, includes assets to preview the avatar in Poser, SLCP, Photoshop, etc.
=== How do I make sure my model looks good from a distance? ===
Experiment with your model on the Aditi test grid. Scale the mesh to its intended size, then watch the model while walking away until you see it disappear. Watch the model as you walk toward it. If the results are not satisfactory, raise or lower the number of triangles in the four automatically generated levels of detail in the upload dialog. Alternately, you may create custom models in a third party program and upload them into the four level of detail slots.
==Intellectual property ==
===How will permission systems work with meshes?===
Meshes have exactly the same permissions system as sculpted prims and textures.
 
===Do I retain intellectual property rights of the meshes that I create?===
Yes, under the Second Life Terms of Service, you retain any intellectual property rights you have in the meshes and other content that you import into Second Life. It's important to remember that you're responsible for knowing your intellectual property rights, and if you're importing meshes or other content to Second Life, you must have all the necessary rights and permissions.
===How can I protect my intellectual property in my meshes?===
As we announced in our Content Management Roadmap blog post, we are committed to empowering content creators to better manage and control their content. 
The protections of the Second Life Terms of Service, Intellectual Property Policy, and Policy on Third-Party Viewers apply to meshes. 
If you believe your meshes are being infringed, you may submit intellectual property complaints to Linden Lab requesting removal of the content at issue as provided in the Intellectual Property Policy. 
===What about models from services such as Google 3D Warehouse or Turbosquid?===
Every mesh you acquire from these and other sites is subject to its creator/vendor's particular license terms, and you must adhere to them. Every individual Turbosquid model contains a license link on its main page, and Turbosquid's Royalty Free Licensing FAQ can be found here. Google's 3D Warehouse Terms of Service can be found here. If any meshes violate either the original creator/vendor's license terms, Linden Lab's Terms of Service or Second Life's Terms and Conditions and Policies, then we will handle the matter as previously mentioned.
===What about content from online marketplaces such as Polyhaven, Ambient CG, or SketchFab?===
Every asset you acquire from these and other sites is subject to its creator/vendor's particular license terms, and you must adhere to them. If any assets violate either the original creator/vendor's license terms or Second Life's Terms and Conditions and Policies, then we will handle the matter as previously mentioned.
===How can I comply with Creative Commons (CC) Licenses in Second Life?===
A list of CC licenses can be found here.
The main components of CC licenses are:
* BY - Attribution must be given to the author.  In Second Life, this may be done by placing a notecard in the object inventory with the appropriate attribution according to the terms of the CC license.  When listing items on the marketplace, you should include attribution in the marketplace listing description. See the CC website for examples of attribution.
* SA - Adaptations must be shared under the same terms.
* NC - Commercial use is prohibited. Material licensed under CC licenses including NC must not be offered for sale.
* ND - Modifications are prohibited. Material licensed under CC licenses including ND may be imported into Second Life but must remain unadapted.  These items should be marked as “No Mod.”
* CC0 - Public Domain. While there are no conditions on how you may use material that falls under CC0 licenses, it’s often polite to include attribution to the original author.
==Performance and stability== 
===Will meshes cause lag?===
Meshes have several advantages over prims and sculpties when it comes to rendering efficiency and quality. First, you need far fewer triangles using mesh versus prims resulting in higher quality and faster rezzing times. For example, a very high quality character model can require only 15,000 triangles using a mesh, while an inferior version requires 250,000 triangles using prims! Additionally, meshes generally have topology that highly optimized for real time rendering, when compared to prims or scuplties, and the result is much faster rendering speeds. However, meshes are a new asset type for the viewer to download and some may require higher bandwidth usage, potentially longer load times, and potentially higher physics loads on the sims. 
Physics simulation is something that we will also be watching very closely, especially in light of our new Havok 7 Havok_7_Beta_Home implementation, that should substantially optimize mesh collision calculations. Regarding heavier bandwidth and longer load times, we will track bandwidth usage and, if necessary, work to make the streaming mesh format as size-optimal as possible and/or impose stricter quotas on the number of meshes that a region can efficiently support.
===Is there a scale limit to mesh files that can be imported into SL?===
At the start of the Open Beta, the default prim scale limit will be 64m. As testing continues and we gather data, we will settle on a size that can easily facilitate your creativity while still ensuring region stability. 
===Is there a file size limit to mesh files that can be imported into SL?===
Yes. The maximum mesh asset size after compression is 8MB, roughly equivalent to a 256MB raw COLLADA file. An entire region can support up to 128MB of distinct mesh assets after compression, not including attachments. The size of attached mesh assets is effectively unlimited, but there's no guarantee that all of your attachments will be downloaded by other viewers.
== Uploading questions ==
=== Why doesn't my mesh upload properly? ===
Please create a thread on our mesh forum ( http://community.secondlife.com/t5/Mesh/bd-p/Mesh ) , and tag it with [UPLOAD]. We're working on creating an upload troubleshooting page, and this will help us to find common trouble areas and answer questions in the future.
=== I cannot upload a mesh. What are the prerequisites of uploading a mesh? ===
In addition to the prerequisites listed on Uploading a mesh model, you must meet the following requirements:
* Using a viewer that includes the mesh feature. Second Life Viewer 3.0+ and some third party viewers are able to view and upload mesh content.
* Standing on land that you can build on. This requirement will be removed in the future.
* Not experiencing a rare billing bug.
=== I'm uploading a rigged mesh (animated mesh to be worn on the avatar) and... ===
Please create a thread on our mesh forum and tag it with [UPLOAD]. We're working on creating an upload troubleshooting page, which will help us answer questions in the future.
For general information on how to upload a rigged mesh, see Uploading and wearing a rigged mesh.
=== How do I test my model on Aditi (test grid) and upload it with the same settings on Agni (main grid)? ===
Second Life saves your model upload parameters; when you upload a model on the Aditi test grid, you can upload it again on the main Second Life grid without needing to re-set all the parameters for the model.
=== How can I reduce the upload fee of my mesh? ===
Identify which of download weight, physics weight, and server weight is largest and attempt to minimize it. Click the Calculate weights & fee button to see these weights.
Download weight:
Use fewer triangles for each of the levels of detail on the model.
Physics weight:
* Physics weight can be minimized by setting Physics > Use Level of Detail to Lowest.
* You can also minimize the physics after upload by linking the mesh to a prim box (making the box the root prim), then setting the physics shape type of the linked set to None. Since the physics type of the root prim of a linked set cannot be set to None, only the box counts toward the object's physics weight.
Server weight:
* Use single "large" mesh models rather than multiple separate meshes.
* Separate and unlink active and dynamic content from passive (unscripted, non-physical) content such as walls or landscaping.
* For technical details on how we calculate server weight, see Mesh Server Weight.
== Land impact ==
=== Why does a mesh cube have a land impact of x when a prim cube is one? ===
Prim count was not a realistic weight of the objects' resource usage and how they affect performance. However, we are not changing their contribution to resource costs on legacy objects in order to maintain existing content.
=== Why does my object's land impact depend on the object's scale? ===
Larger objects have a higher streaming weight -- they are visible from a greater distance (which means they need to be streamed to more viewers in an area). An object's scale can also increase or decrease its physics cost, depending upon the object's shape, physics type, and the way in which its physics model was generated when you uploaded it.
=== Why do meshes have x land impact when they have the same number of triangles as a sculpted prim? ===
Prim count (in which a sculpted prim counts as 1) was not a realistic weight of the objects' resource usage and how they affect performance.
 
=== Why does my land impact go up when I add a script? ===
The land impact of an object increases when you add a script if the land impact was determined by server weight. This happens only when the server weight is higher than either the streaming or physics weights of the object. Making an object dynamic (physical or scripted) increases the amount of work the server has to do to track that object. Most often, objects have a higher streaming or physics weight than server weight, so this only affects certain server-intensive pieces of content.
=== Why does my land impact go way up when I link a mesh object to a prim (eg. torus)? ===
We want to more accurately display the true resource usage of content on the systems of Second Life and your computer. A torus prim is "only" one prim, but it actually creates a much larger load on the physics engine than other, less complex prim types such as a box or sphere.
* For instance, I have also noticed this occurring when I Link to just a one prim cube. 
* Solution you could add a script to unlink the mesh objects from the rest of the objects when you put in place.
=== I linked my mesh to a torus and its land impact went way up. How do I bring the land impact down to a reasonable value? ===
Set the Physics Shape type of the torus (found on the Features tab of the Build Tools window) to Convex Hull. The hollowness of the torus creates a high computational load on the physics engine. Setting it to Convex Hull simplifies the physics of the torus by putting a cap on the top and bottom, meaning you will no longer be able to stand inside the torus. If you don't need to collide with the torus at all, set the Physics Shape type of the torus to None. Note that the root prim of an object can never be set to Physics Shape type of None.
=== Why does my prim object's land impact go up when I make some prims have no physics shape? ===
When any prim in an object is set to a physics type other than "prim", the entire object's land impact is calculated using land impact measurements instead of the traditional prim count. This means that some prims in the linked set may be assigned a cost higher than one.
=== How can I reduce the land impact of my uploaded mesh? ===
# Edit your object and click More Info.
# Figure out which of download weight, physics weight, or server weight is highest and is therefore driving your high land impact.
#* For objects with a large physics weight, a simple 2 step process can lower the land impact. Set the Physics Shape type of the root prim and any prim that needs a physics shape to Convex Hull, then set the Physics Shape type of the rest of the prims to None. The Physics Shape of the root prim cannot be None.
#* For objects with a large streaming weight, try reducing the scale of the object or provide better-optimized levels of detail that reduce the number of triangles drawn when the object is viewed from a distance.
#* For objects with a large server weight, try making the mesh out of fewer pieces, link small objects together, and remove scripts from the object.
=== What is one example of how land impact calculations work to my benefit when compared to prim count? ===
Since physics is now calculated separately from streaming or server weight, you can simplify the physics weight of an old prim-based vehicle to something less than 32, allowing you to add more than 32 prims of visual detail without compromising the vehicle's physics performance or vehicle status.
=== Avatars and clothing have no land impact limits. What numbers should I aim for? ===
There are a few options for determining how much impact your attachments have:
* Turn on wireframe mode and take a look at your attachments. If they still look solid, it is likely that they contain more triangles than are necessary and are incurring too much streaming cost on the people around you. You can turn on wireframe mode in the Develop menu by choosing Develop > Rendering > Wireframe.
* Turn on Avatar Rendering Cost to see the overall impact of your avatar. ARC uses a different rating system than land impact; for more information on Avatar Rendering Cost, see Avatar Rendering Cost.
== Advanced questions ==
=== Why can't I import the model I created? ===
Please check the troubleshooting guide for some common problems.
=== I want to animate my mesh. Why can't I use UUID flipping? ===
UUID flipping is being throttled on mesh to prevent the creation of objects that animate this way. Learn more about why UUID flipping is bad, and what you can do instead.
=== How do I mirror a mesh? ===
Sorry, we don't support this feature yet. We do plan to support mirroring later on.