Using Audio Materials
Audio materials let you set objects to a specific material type. This is advantageous when you want to alter the way sounds play in a scene.
Uses for audio materials
Reverberation and occlusion
You can take advantage of audio materials in order to set the way sounds bounce off objects and through objects in a scene.
In Sansar, you can set sound waves to bounce off objects in a scene, which can create interesting reflective sound behavior. This is referred to as reverberation. For example, singing in the shower produces a more echoey sound compared to singing in other rooms. This is mostly because bathrooms have tile, metal, and other reflective surfaces that have different properties compared to a living room with reflection-dampening rugs.
To enable this, you must turn Compute reverb on. When compute reverb is on, occlusion will also be enabled in the scene, which affects the way the sound passes through objects. For example, sounds that is generated on one side of a wall will sound muffled or dampened as it passes through to the other side.
You can alter the way sound is produced in a scene by following these steps:
While editing a scene, turn on Compute reverb in the scene settings panel. To know more about how to turn this on, see steps here.
Click on an object that you want to apply the audio material on.
Open the object's properties panel. Read more on how to edit an object's properties panel here.
Look for Audio material on the audio settings section of the properties panel.
Click the dropdown beside Audio material and choose a material.
To preview how the sound bounces off objects, build your scene.
Try out the various audio materials in your scene with reverb on to see how reverberation and occlusion affect sounds as they bounce.
Footstep sounds
Audio materials also affect footstep sounds when assigned to walkable objects or terrain. For a quick comparison of the audio materials available in Sansar, visit Creator Academy: The Hall of Materials. In the experience, notice the pads at the end of the hall to hear the audio material type as your avatar walks over the pads.
You can alter the way footsteps sound as avatars walk over the object surface or terrain:
While editing a scene, click on a terrain or an object that you want to apply the audio material on.
Open the object's properties panel. Read more on how to edit an object's properties panel here.
Look for Audio material on the audio settings section of the properties panel.
Click the dropdown beside Audio material and choose a material.
To hear how the sound bounces off objects, build your scene.
Note: Compute reverb does not need to be enabled for footstep sounds. However, when it is on, reverberation and occlusion also applies to footstep sounds.
Find the Audio materials dropdown menu in the object or terrain's properties panel.
List of audio materials
In Sansar, there are various preset material types that model their real-world, physical counterparts. Here is a list of the audio materials available in Sansar:
(Generic) - Default: neutral-sounding footsteps. Similarly subtle reverb. Medium-strength occlusion effect, like hearing something through typical home walls. Sorted to top of list.
Brick - Crisp footsteps. Long reverb. Strong occlusion — all in all, just another brick in the wall.
Bushes - Crunchy, varied footsteps with a lot of overlap. Useful for simulating walking through twigs and other organic matter. Weak occlusion that softens the sound a little.
Carpet - Very subtle footsteps unless you're running. Very absorbent and strong occlusion, which makes carpet a good dampening material with barely any reverb.
Ceramic - Highly crisp footsteps. Can also be used for marble tile and similar substances. Strong reverb. Occlusion softens low frequencies more than high ones.
Concrete - Crisp footsteps. Useful for interior industrial spaces like warehouses and factories. Strong occlusion, like a very thick concrete wall would be.
Dirt - Crisp organic footsteps. Highly absorbent. Occlusion is fairly strong.
Glass - High-pitched, clinky, fragile footsteps. Fairly strong reverb. Occlusion dampens low and high frequencies more than midrange.
Grass - Crunchy footsteps with some overlap. Pretty quiet. Use in combination with "Bushes" for naturally-varied terrain. Barely occludes at all.
Gravel - Crunchy footsteps with occasional overlap. Relatively louder than "Dirt" and "Sand", like how real gravel would be. Occludes less than "Dirt".
Metal - Clangy, metallic footsteps. As the name indicates, generally useful for metal platforms, stairs, and similar surfaces. Strong reverb. Medium occlusion with midrange frequencies more noticeable.
Mud - Squishy footsteps. The footsteps sound more splattery while running. Also useful for ground transitions between Dirt/Gravel/Sand and Water. Occlusion is similar to the Water material.
Plaster - Somewhat muted footsteps. You could use this as a milder alternative to "Brick". Long reverb. Fairly weak occlusion, like fragile plaster surfaces.
Rock - Crisp footsteps with some subtle grit, simulating walking on larger rocks with smaller stones interspersed. Relatively strong reverb and occlusion, suitable for caves and tunnels.
Sand - Scattered organic footsteps. A quieter and finer texture than "Dirt" or "Gravel". Occludes fairly strong, like "Dirt".
Silent - Blocking - No footstep sounds. No reverb at all. Occlusion totally silences sound from the other side of a collidable, making it useful for segregating sound in small spaces.
Silent - Nonblocking - No footsteps. this is totally acoustically transparent and passes sound through without alterations. Useful for invisible walls you want only blocking navigation, not sound.
Snow - Crunchy, varied footsteps with a lot of overlap. Running gives the footsteps more impact. Naturally complements tundra terrain. Moderately weak occlusion, but still noticeable with higher frequencies.
Water - Loud, splashy footsteps, wading through water. Occlusion removes high frequencies and dulls the low-end, making things sound muffled.
Water - Shallow - Similar to the regular water audio material, but with shorter, milder liquid splashes during footsteps. Apply this to puddles and standing water.
Wood - Crisp footsteps. Noticeable reverb. Moderate occlusion, except for dampened high-frequencies.
Wood - Creaky - Has a lot more "personality" than the general Wood material, with lots of wear and tear. Keep running and you'll hear very loud squeaks — suitable for haunted houses and rickety bridges! Moderate occlusion, except for dampened high-frequencies.
Wood - Plank - Related to Wood, but with a lower pitch. Like walking on a boat dock, or just use it to add variety to parquet surfaces adjacent to regular Wood. Moderate occlusion, except for dampened high-frequencies.
Some types share the same footstep foley yet have different reverb properties, while others have their own unique footstep sounds. For example, even though gravel, dirt, and sand are all made of small bits of earth in the physical world, they have distinct sonic identities.
Tips and best practices
When using audio materials, you don't need to be literal about matching an a material type to a walkable surface. You can mix and match material types with any object or walkable surface— regardless of the material name, trust what sounds right. For example, you might have a dull metallic surface that feels more convincing with "Concrete" than "Metal".
As with other Sansar audio features where spatial audio can be a key contributor to immersion, we recommend you test your own experience with a good pair of headphones, and, if possible, in VR mode.
Room size matters with reverb. Setting a really big room (with collidable walls on all sides) to a highly reverberant audio material will sound a lot more “echoey” than a small room with the same audio material.
Audio materials only fully work with static physics shapes, which may be associated with a mesh object or exist by themselves. To toggle physics shapes, go to Visibility > Physics shapes. The static shapes appear in gray. Dynamic shapes that appear in yellow will work with footstep sounds, but are ignored by reverb and occlusion. Related, see "Making an object dynamic".
You may find it easier to assign audio materials to objects by momentarily hiding Visibility > Meshes and focusing on the actual collidable areas. Remember, audio materials won't work if they're applied to an object without a physics shape, since those are effectively "phantom" objects that your avatar or other objects pass through.
Audio occlusion only applies to the nearest collidable to your camera (your "listening point"), because it can be computationally expensive. For example, if you're in 1st or 3rd person view and there are several "walls" in between you and an audio emitter, only the audio material of the closest wall to your avatar has an effect. Even if it's set to be a weaker audio material than the walls behind it — say for example, a grass hedge in front of brick walls — the nearest wall always takes precedence. While fairly uncommon, this can result in a strange sensation of "hearing through walls" at closer distances. We recommend you thoroughly test your experience, and generally design for the nearest collidables in key navigable areas to also be the strongest audio materials.
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