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sb526

Redshift proxy trees & alpha maps

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Hi all,

I have made my first redshift proxy. It seems when I load it there's a white 'halo' at the edges of my leaves which disappears on close up scale but becomes super noticeable further out.

What's the best way to fix this? Is it due to the alpha map being too low res? Same FBX model in Mantra renders with no issues.

 

On a side note, are there any good resources to buy Redshift ready vegetation assets? I have found Megascans to work well for smaller elements but it lacks larger tree models. I know there's Speed Tree but I am looking for something more 'ready made'

 

 

image.png.0a55dcca096c89ede890da9e86fc9013.pngimage.png.6ff277f2d428c64f08592ffafd2023cf.png

 

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Posted (edited)

Isn't that just a pre-multiply problem with your texture's alpha? Look for a checkbox on the texture sampler.

Edited by Atom

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It's weird because leaf textures usually have a green background. You shouldn't have that white border. It might also depend on how you apply the alpha.  Png or tif with alpha or jpg with separate diffuse and alpha?
For foliage I strongly recommend using rs_sprite which makes a noticeable difference to render times.

Could you post a reduced version of the model with the texture (not the proxy)

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@Atom

I was using the same PNG that came with the asset & rendered with no issues in Mantra. I used a color splitter to extract alpha in RS mat. Couldn't find a pre-multiply check box.

 

@flcc

Attached the file and texture. Texture is a simple PNG file nothing too fancy. I am extracting alpha via RS color splitter.

I will try the RS sprite workflow thanks for the tip!

 

 rs-asset-prep.hipnc

DB2X2_L01.png

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Posted (edited)

I don't see any problem with the png file. It has black bg. It can't generate white halo.

However, in your file the Alpha is connected to the bump input. it can be a reflection artifact.

Edited by flcc

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2 hours ago, flcc said:

I don't see any problem with the png file. It has black bg. It can't generate white halo.

However, in your file the Alpha is connected to the bump input. it can be a reflection artifact.

 

Thanks for taking a look!

My alpha is connected to opacity_color input of the RS material node.

I thought this was the alpha? If not, which one is it?

 

image.png.d3baf764622fed210d2c8f6cba906b09.png

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Posted (edited)

In the file you've posted Alpha is connected to bump-input but in the capture above it's ok.

But anyway, testing your file I'm not sure if I see the "white artifacts" you show in your first capture.

My guess is a reflection problem. The leave geometry is flat polygon and roughness is to high. With a white Dome this result in many totally white leave.
I've reduced the roughness and add a  bump noise to beak the leaves flat surfaces.

By the way I also put a sprite material. With this kind of object i.e. hardwoods, Renderings can be up to 8x faster.

rs-asset-prep F.hipnc

Edited by flcc
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Awesome, thanks for taking a look. Sprites make rendering time so fast!

I loaded in my texture and was still getting a tiny white halo around leaves in both sprites and normal workflow.

What ended up completely fixing it is switching Filter to 'none' in RS Texture > Advanced tab.

 

P.S. I did not know RS has Maxon noises node. The more you know.

 

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Posted (edited)

Yes Maxon noises is a nice addition.

For you white halo, it's very strange as I don' get it, and also because the background of the png is black.
Having to disable filtering is not normal. It's look like a bug.
You can also try to separate the png into two jpg, this will give you some clues

May be try another version. Or ask on the redshift forum.
Little bugs come and go quite frequently, especially in the houdini version.

Edited by flcc

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Good point. I am on Houdini 18.5.462 and some trial 'latest' version of Redshift 3.5. Might be a bug or trial limitation.

Need to try on my work PC with H18 RS 3.0 license.

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