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I'm new to the exchange, I am going around in circles trying to get my nodes setup correctly in blender cycles. The basic setup is that I have a brick texture, which I want to overlay/mix 2 grunge textures with transparency in. However, although everything appears fine in material view, which is how I want things to appear, when rendered everything is black. I've eliminated lighting as a problem. I've read article after article on using transparent images in cycles as well as watched several youtube videos, but still my setup seems to be wrong. Maybe what I am trying to do isn't possible.

I've uploaded the blend file to my onedrive, so you can take a look at it, bare in mind I am no artist and this is a simple model for uploading to a virtual world, so it's nothing fancy and I'm still learning, so my geometry might be a little rubbish too. lol

If someone could set things up for me, I would appreciate it, then I can learn from what I see.

The blend file can be found here: https://pkamc-my.sharepoint.com/:u:/g/personal/atlockey_myoffice365_site/EQcTn5iMnZdHpNzOjup10XoBXa1WnJrgr1239vGw4osPpw?e=9KHroh

Cheers

Andy

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  • $\begingroup$ It doesn't look like your texture images have been packed in with the file. Your environmental images have, but your model texture images are not there. File > External Data > Pack images with .blend. This option embeds your texture files into your Blend file. $\endgroup$ – OroNZ Feb 6 '18 at 2:09
  • $\begingroup$ Sorry for the delay, for some reason they weren't packing, they should be now, touch wood, I'm not having much luck today lol $\endgroup$ – Frank N'Stein Feb 6 '18 at 3:17
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    $\begingroup$ Hi. Please add images to your question so that it isn't isn't fully dependant on downloading your file. $\endgroup$ – Ray Mairlot Feb 6 '18 at 5:07
  • $\begingroup$ Now there's a prob with downloading the file :) But I had a look at the first file. You have two major probs with your node trees. First, always try and match output colors with input colors. You're trying to use Mix SHADER nodes (green I/O) as inputs for COLOR nodes (yellow I/O). Second, you need a shader as your last node before the Output. Bluntly speaking, shaders 'shade' polys with the required surface qualities: diffuse, transparency, bump, gloss, emission, etc. Everything else is about determining the color or pattern of the shader. $\endgroup$ – OroNZ Feb 6 '18 at 5:32
  • $\begingroup$ @ OroborosNZ. Sorry about that when I overwrote the file in my onedrive, the sharing permissions and link changed, I have an updated link below. So from what you are saying, the problem most likely lies at my use of the RGB mix shaders, I've added a shader as my last node before the output, that works for showing the brick texture in render mode, so that's progress, it's just the transparent images that need sorting. pkamc-my.sharepoint.com/:u:/g/personal/… $\endgroup$ – Frank N'Stein Feb 6 '18 at 11:14
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You're mixing up shaders with texture compositing operations.

The shaders are the ones with the green sockets, and you should never connect other colours to the green sockets or vice-versa.

The yellow and gray sockets are used for colours and values respectively. In practice it means you'll use the yellow sockets to add colour textures to your shaders inputs, and grayscale textures (or single values) to control properties.

(that's a gross over-simplification, but it will help to have a minimum grasp of what you should/shoudn't connect to each type of socket).

With the above in mind, remember that you can mix and combine textures BEFORE connecting them to a shader. So in this case you should use mixRGB nodes to combine them and plug the result to the shader.

In your example of brick texture and grunge textures it would be just matter of blending the first grunge texture over the brick texture (using a mix node if the grunge one has alpha channel will do, but you could also use a different blending and connect the second texture's alpha to the Fac input to drive the mix).

Once you did that, the output of that mix will be textures 1 and 2 blended, so you only need to add another mix and blend the third texture over.

That will be your "combined" texture that you will plug to the colour socket of your shader (most likely a diffuse shader).

You can add further work to your shader if you need some glossiness or other surface properties to your material, but that's basically the procedure of combining textures.

*) Note that mixing two shaders (one transparent and an emissive/reflective one) to create a material with transparency based on a texture's alpha is a completely different procedure.

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Right basically the mistake I was making was as pointed out by Oroboros, I was plugging the outputs from the mix shader of my transparency setup into the colour inputs of my RGB Mix Shader, so it was a green dot to a yellow dot. (as per first picture) enter image description here So I unplugged that setup and ran the colour output from my Texture node directly to colour input of the RGB Mix shader as well as leaving it going to my transparency setup and additionally ran a second alpha output up to the RGB mix shader's factor input. (As per picture 2) enter image description here It seems like a lot of spaghetti for a simple task, so I can't be sure it's all needed, however it works, so I'm leaving well alone.

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