Mesh collidersAn invisible shape that is used to handle physical collisions for an object. A collider doesn’t need to be exactly the same shape as the object’s mesh - a rough approximation is often more efficient and indistinguishable in gameplay. More info
See in Glossary require a GameObjectThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
See in Glossary’s MeshThe main graphics primitive of Unity. Meshes make up a large part of your 3D worlds. Unity supports triangulated or Quadrangulated polygon meshes. Nurbs, Nurms, Subdiv surfaces must be converted to polygons. More info
See in Glossary to be properly configured so that collisionsA collision occurs when the physics engine detects that the colliders of two GameObjects make contact or overlap, when at least one has a Rigidbody component and is in motion. More info
See in Glossary are accurate.
There are particular configurations and optimizations that require a Mesh to be read/write enabled. For details on what “read/write” means in this context, refer to documentation on the Mesh API property Mesh.isReadable
.
A Mesh must be read/write enabled if any of the following circumstances are true:
To make a Mesh read/write enabled, the Mesh must have a Mesh.isReadable
value of true
. To apply this via the Editor:
Assets
folder (Project tab) More infoTo calculate collisions with a Mesh collider, the physics system needs to be able to access the Mesh’s geometry. “Mesh cooking” refers to the process of converting a 3D mesh from its original format (for example, FBX or OBJ) into a format that the physics system can read. The cooking process takes the raw Mesh data and builds spatial search structures so that Unity can respond to physics queries more quickly.
You can trigger Mesh cooking in the Import Settings (Import Settings > Model > Generate Colliders) or at run time.
During the Mesh cooking process, Unity can apply various optimizations to reduce the size and complexity of the Mesh (for example: removing redundant vertices, merging overlapping triangles, or simplifying the geometry to reduce the number of triangles). Unity can then load the optimized mesh more quickly and efficiently, which reduces memory use and improves overall performance.
To control which optimizations run, use the Mesh collider’s Cooking Options property (which corresponds to the C# enum MeshColliderCookingOptions
). For an overview of the different cooking options available, see the Mesh collider component reference.
The default Cooking Options are suitable for any Mesh collider that you cook in the Editor and never re-cook at run time. They are also suitable for most Mesh colliders that you need at run time (particularly large or complicated Meshes that only need to cook once). However, you might need to alter the Cooking Options to make collider generation faster if you need to rapidly generate collision geometry at run time (for example, procedural surfaces, or Mesh colliders that deform in response to player behaviour).
To optimize Mesh cooking for Meshes that Unity generates at run time, you can disable the data cleaning steps (Enable Mesh Cleaning, and Weld Co-Located Vertices). However, if you disable the data cleaning steps, you must have another way to validate your Mesh data, to ensure you aren’t using data that those algorithms would otherwise clean.
You can also disable Cook For Faster Simulation to save memory usage.
When you change the Cooking Options, you need to apply read/write permission to the Mesh. For guidance on how to do this, see Allow read and write access to a Mesh.
If a Mesh only needs to provide data for physics calculations and not for rendering (for example, for invisible colliders), you don’t need to import the Mesh’s normals. Meshes without normals require less memory and use less disk space.
To disable normals:
Did you find this page useful? Please give it a rating:
Thanks for rating this page!
What kind of problem would you like to report?
Thanks for letting us know! This page has been marked for review based on your feedback.
If you have time, you can provide more information to help us fix the problem faster.
Provide more information
You've told us this page needs code samples. If you'd like to help us further, you could provide a code sample, or tell us about what kind of code sample you'd like to see:
You've told us there are code samples on this page which don't work. If you know how to fix it, or have something better we could use instead, please let us know:
You've told us there is information missing from this page. Please tell us more about what's missing:
You've told us there is incorrect information on this page. If you know what we should change to make it correct, please tell us:
You've told us this page has unclear or confusing information. Please tell us more about what you found unclear or confusing, or let us know how we could make it clearer:
You've told us there is a spelling or grammar error on this page. Please tell us what's wrong:
You've told us this page has a problem. Please tell us more about what's wrong:
Thank you for helping to make the Unity documentation better!
Your feedback has been submitted as a ticket for our documentation team to review.
We are not able to reply to every ticket submitted.
When you visit any website, it may store or retrieve information on your browser, mostly in the form of cookies. This information might be about you, your preferences or your device and is mostly used to make the site work as you expect it to. The information does not usually directly identify you, but it can give you a more personalized web experience. Because we respect your right to privacy, you can choose not to allow some types of cookies. Click on the different category headings to find out more and change our default settings. However, blocking some types of cookies may impact your experience of the site and the services we are able to offer.
More information
These cookies enable the website to provide enhanced functionality and personalisation. They may be set by us or by third party providers whose services we have added to our pages. If you do not allow these cookies then some or all of these services may not function properly.
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
These cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites. They do not store directly personal information, but are based on uniquely identifying your browser and internet device. If you do not allow these cookies, you will experience less targeted advertising. Some 3rd party video providers do not allow video views without targeting cookies. If you are experiencing difficulty viewing a video, you will need to set your cookie preferences for targeting to yes if you wish to view videos from these providers. Unity does not control this.
These cookies are necessary for the website to function and cannot be switched off in our systems. They are usually only set in response to actions made by you which amount to a request for services, such as setting your privacy preferences, logging in or filling in forms. You can set your browser to block or alert you about these cookies, but some parts of the site will not then work. These cookies do not store any personally identifiable information.