VrayDisplacementMod - Problem with the Fixed Image Sampler

[mrbombastik]

Hi,

In my scene i want to model the grass with the VrayDisplacementMod.

 

First to say that i generally model buildings having decorative elements such as corbels, balustrades, decorative cladding panels etc. and so i generally prefer "Fixed image sampler" to see the details in my final render. Indeed i had tried adaptive dmc and sub. before but they did not satisfy me for the buildings having detailed decorative elements.

 

I haven't need to model the grass for now. Actually a simple grass mapping goes ok for my models as the building is always taken into consideration.

 

And now there comes the need to model grass more realistic in my latest project. I used VrayDisplacementMod but Fixed image sampler does not cope with the vraydispmod i think as you can see in the attachment.

There are black dots, points distributed all over the grass.

 

Adaptive dmc and sub. seems ok. Not precise in the attachment but seems to be improved anyway i think. But fixed image sampler result is a mess for me. I don't want to deal with the adaptive samplers because i don't want to leave my render setup based on the fixed image sampler which is inevitable for me.

 

Anyone having suggestion or experience like this?

 

*As a solution; I tried to bake the grass (the plane in my scene) with adaptive and then applying the texture and switch back to fixed for the final render but i could not manage it really. The vray complete map give a nonsense result.

[danb4026]

What are you using as a displacement map?

[Dave Buchhofer]

Why are you using a fixed sampler of 1? AKA: No Anti Aliasing, meaning that for each pixel, it will only put up 1 color.. so for cases where there is more detail inside of 1 pixel, anti aliasing blends between the various sub-pixel colors to bring you a more averaged representation of whats in that place.

[mrbombastik]

well i don't use a bitmap for this model, i created a mixture of black and white with some noise. White dots on black surface.

 

By the way i should say i had faced the same problem with the Fixed image sampler when using vraydisplacementmod for a carpet, even using bitmap for the displacement.

[mrbombastik]

Dave,

Sometimes mind really tries to solve a problem thinking about complex situation and denies to choose the simplest way actually

thank you for giving brightness to my messed mind.

 

But something get me this point which is: in my previous work, i had tried to generate a carpet by same method vraydisplacementmod but that time i had used a bitmap texture for the displacement as i mentioned in my previous post, and i had got same result(black dots) and as far as i had used texture i had not tried fixed as "3" as I have always considered anti alias as smoothing edges and no relation with the texture. I still have the idea as it is for the edges.

 

In this project i have not used a texture, it is a mixture as i mentioned. I think that made the difference.

 

I have in an urgent time of completing this project. I will try fixed 3 for the carpet having texture for displacement. Maybe you know exactly what will happen?

 

thank you for dealing

regards

[WAcky]

Why are you using the Fixed sampler at all??

 

Its really only useful for test renders...

 

If you use the adaptive subdivision with settings of say 2/4 then it will see the grass as needing more detail and sample it at 4 sub divs, then in areas like sky it will take the sampling down to 2 sub divs.

 

The fixed sampler is just so inefficient...