Reimporting SpeedTree Assets

I created some grass in SpeedTree, saved it as a spm (it created a srt to go along with it). I imported it in UE4 and all works fine (it generated a material and texture). Now I’ve made some changes in SpeedTree however, saved it again, reimported in UE, but nothing happened. Is this something that’s not supported?

For me the model, the actual tree gets updated but not textures or materials. I don’t really use those though, I have my own material and import textures separately so I can reimport hem easily if I need to edit them in Photoshop or something.

That’s exactly it, the texture doesn’t update. I haven’t adjusted the model yet.

For now, you’ll need to reimport the textures manually. I have submitted changes for the SpeedTree reimporter to do that automatically, but they haven’t been merged in yet.

Thanks for the update Greg. Rather than creating a new thread I hope I can poke your mind regarding a few other things… Namely the generated textures. Textures with alphas, namely leaves or grass strands have a rather ugly white outline, as if the alpha mask doesn’t fit properly. I double check it in Photoshop and it seems to be alright. Are there some settings to tweak this? An alternative to TGA files? Perhaps something to adjust in the compiler?

You probably need to streak (aka dilate) the color channel from the opaque parts out into the transparent parts so mipmapping doesn’t pull in the surrounding colors, which is probably white in your case. We do this when we make billboard textures, but we don’t touch your source assets… Though maybe the SpeedTree Compiler could have that as an option in the future. I’ll log to look into it.

I googled and found an in-depth description of the problem and a photoshop action you can use to get similar results.

I’'ll test this out first thing tomorrow, thanks!

Hey Greg, your solution worked great, thanks!

In the process however I ran into another question - is it possible to control wind speed of speed tree foliage from within UE?

There is an actor called Wind Directional Source (I think) that one can control direction, strength and speed of the wind, which affect Speedtree wind.

Thanks a lot guys, SpeedTree is now working flawlessly.

Feature request though - auto login on program launch & metric units pretty please. Literally the only complaints I’ve got about it. Keep up the good work!