[bruno.sdi]

Hi there,
Is it possible to have a non linear interpolation for the transition between the root and tip of the grass blades? As far as I can see, those parameters can not be mapped, so I assume it is not possible... I guess we can use alphas to make that transition but it would probably lead to some artefacts specially if having single sided sss materials applied right?

Cheers!

[Mihai]

It shouldn't create artifacts....just set root/tip to be the same and use an alpha to shape the blade the way you want. I'm pretty sure also that the less the alpha cuts away from the blade the better, meaning a very large real geometry that is cut to only 5% visible by an alpha will render less efficiently than an alpha that cuts away very little. So try to make the initial blade geo at least about the same general wideness it would have without an alpha.

[bruno.sdi]

Hi Mihai,
Thanks for your reply. Did a test last night with alphas, and indeed didn't get any artefacts. With the root / tip the same width and set the alpha the same size as the grass blade, so basically it cuts out about 5% only like you say. The only thing with this technique is that you have to have a few grass extensions with different alphas applied to get a good randomisation, but at least works pretty well.

It would still be good if one could have some sort of variation to the root / tip of the grass on each grass extension without using alphas...

Just as a side note, I ran a few tests with and without alphas and the time to reach the same SL is almost the same (the one without alpha being slightly faster) but the benchmark is lower with the one with alphas.

Thanks again.