i am work with unity’s detail mesh brush. because unity only support billboard grass,but i need a little more,so i use detail mesh brush to create grass with “X” shape,just like other game does.
but now i have a problem,i want the grass mesh vary on the size and maybe the rotation on the y axis,but strange thing happened,on some terrain trunk,it work just fine,but on some truck,the mesh just upside down,namely the grass grown downward! but if i change the mesh,it became just good.
so i want why this happened,is it a bug?
or someone can tell me how the detail mesh random system works？
or maybe someone can tell me how to work around
thanks!
Sounds like you have issues with your pivots. Open up the models in question in your 3D App of choice and make sure the pivots are set properly and don’t have strange rotation or positions. The pivot should sit at Y=0 if at all possible. I usually center my pivots right at 0,0,0 on all axis if I can.
thanks for replying, but it seems not the problem, i have fellow this post:
http://forum.unity3d.com/threads/29320-How-to-create-my-own-quot-detail-mesh-quot-and-paint-it-on
but what i mentioned is another problem,i found when the grass is upside down,if i change the parameter of detail mesh ,such as noise spread to some value ,the problem disappear ,but i dont konw the inner relationship of them,and at the same time, when i change the parameter,some mesh that is good goes upside down !..
do you have any idea about this?
It’s happening with a brush set I bought from the Asset Store. I’ve also had it happen with a set of scrubby bushes I made with the Tree Creator. The problem is that it’s not EVERY item painted onto the terrain but just a few. The problem seems to have a relation to the noise setting and size. If it happened every time I would fault the asset but that’s not the case so you focus in on the editor. I reported this as a bug.
I am having the same problem. Setting noise to 1 does a good job of fixing it, but that shouldn’t be necessary. 
