Displacement seems to lift colour from underlayer....can this be prevented ?

[pclavett]

Hi all !
I have time to toy around with TG2 at this time and was trying to concoct a good grass surface layer and practiced with only the node complex connected to the planet without input from the terrain..that is on a perfectly flat plane. When it came to plug this into a complete tgd, that is with a terrain and base colour node coming into the input....to my surprise the thing did not look the same....a lot of greyish colour mixed in with the green...exactly the color from the base colour node. It appeared that the displacement for the grass was pulling the colour up and the greater and coarser the displacement, the greater the amount of grey. I proceeded to put another surface interpolated between the base colour and the grass layer and turned on the test colour and take a look at the purple field that came up. I then proceeded to factor in the same colour node for the grass layer into the interpolated layer (turned off the test colour of course) and then obtained a nice field that looked more natural and this time no grey as the displacement was likely "pulling" up the same colours as the grass layer itself. Now I have been working on and off with Terragen for several years and unfortunately likely not regular enough to take notice of some things but this notion of the displacement "picking" up underlying colours is a new notion for me and will certainly influence my thought process when planning things in TG2. Am I totally off the wall with this interpretation of what I noticed or am I analyzing this OK Any comments are welcomed !
I appreciate your input and hope someone can enlighten me on this !
If I am interpreting this the right way.....is there a setting that will prevent this lifting of colour ?
Thanks and have a great day !

Paul

[Tangled-Universe]

I think you may wanna have a look here:

http://forums.planetside.co.uk/index.php?topic=6701.msg71067#msg71067

and here:

http://forums.planetside.co.uk/index.php?topic=4814.msg50282#msg50282 (NB: now the surfacelayer does have the function Matt discusses there)

[pclavett]

Thanks Martin !

I initially did not understand your directing me to the said articles or threads but when I checked the grass layer I had set some restriction to slope even though I was set to a level  non-generated terrain. The max slope was 60.
When I turned that off...problem resolved ! I include several renders to illustrate, the underlying surface being "test colour" activated for easier demonstration. Note that with the restriction, the colour is limited to the tip of the spikes, the rest probably exceeding the slope of 60 being vertical spikes. With the restriction off, the spikes are green now and the look is what I was trying to get. I proceeded then to use the distribution shader to restrict the slope and show the images obtain with the change of the slope key from "final normal" to "terrain normal". Problem is solved !

Thank you Martin for the info and hope this will help other newbies such as myself !

Take care !

Paul