Training Stream - Materials / Particle Interactions - May 26th @ 2PM ET

Developer Relations Technical Artist Alan Willard will show us how to get the most out of Materials and particle interactions in Unreal Engine 4 and take your questions on the subject live. If you’re looking to up your game in tech art, this one is a must!

Tuesday, May 26 @ 2PM EST - Countdown]


Alan Willard - Developer Relations Technical Artist

Feel free to ask any questions on the topic in the thread below, and remember, while we try to give attention to all inquiries, it’s not always possible to answer everyone’s questions as they come up. This is especially true for off-topic requests, as it’s rather likely that we don’t have the appropriate person around to answer. Thanks for understanding!

Edit: The YouTube archive is now available here](

What the best way to make realistic 3d footprints in tessellated snow? Also how to prevent gpu particle effects from colliding with my character?

I’d love to see in example of Mortal Kombat style blood with collision-producing blood stain decals.

Hi, when We can see a new particle editor? pre alpha maybe? and more particle tutorial pls

1 in vehicle game template i find ground tire particle, and can’t understand how Epic make spawning dust on moving(if particle stiil dust don’t showing but if it move in space dust start showing)
2 How to create wheel trail in cascade? from scratch?

also i have problem with immediately disappearing particles when i change one template on another

Can you guys please improve the decal system? So decals display properly across multiple objects (for example both the wall and floor) when spawning them?

Unreal tournament currently suffers from this problem too, when you fire the bio rifle at a spot where the wall and floor intersect, it will stretch very bad across one of them. There is no true seamless decal projection

Is there a possible workaround for this? Or is it just a limitation and a more complicated solution is needed?

Sadly there isn’t a really good universal solution to this problem (I did a bunch of work on Torque3D’s decal system in the past and tried to fix this).

I suggest doing 2 or 4 raycasts when you shoot, offset to cover the edges of your intended decal size. Then, spawn the decal with an averaged normal. It won’t be perfect by any means but it should eliminate the most egregious stretching.

I have a few questions about the optimization. I know the answers are not Manichaean and ever case is different but general advices are welcome :slight_smile:

  1. What is the cheapest way to do particles ? Is it to make lots of particles with lower definition textures of higher definition textures with lower rate of particles ?
  2. Is there any easy way to smooth the contact betweeen sprites and geometry, to make something not penetrated but more realistic
  3. I gess environnement particles has to be treated differently than instant particles so what are the best and cheapest way to add environnement particles at the lowest price ? (baking, stop dynamics, etc)
  4. Is there any way to spawn particles through a greyscale texture (white 100%, black 0%) ?
  5. Is there any way to set a selected low-poly static mesh which will decide initial direction ?

thank you guys :slight_smile:

wow! :stuck_out_tongue: Looking forward to this stream.


  1. Can you go over the best practices for dealing with physical materials with skeletal meshes. PhysicsAssets versus Material settings. For example, If I have a collision component but have a 2 different material inside of that volume for flesh and armor. In addition(more of a request), if I have a single material that has UV areas that are metal and UV areas that are flesh, is there any system to assign physical materials based on UV space?

  2. +1 on Decal best practices especially for characters in game. In some cases, decals don’t work well with shadow areas in general without turning on engine settings such as


3.) Emit particles from material uv/id masks instead of just bones? Aw yeah???

Should be a great session! Thanks!

My materials are starting to look really messy and hard to follow even after using material functions. Can you point out some tips and tricks to eliminate clutter and avoid strings stretching across materials to reach nodes?