I'm doing a scene which is intended to be a horror/goth T-shirt transfer. Part of the scene has a skull sitting in a puddle of blood. I tried taking your Milk shader and adapting it, but it didn't turn out so well. After several tries of various materials, right now I'm using an old Fresnel water shader I made years ago that I called my "blood water", but it still doesn't look quite right. So I have come asking your opinions. Oh, and by the way, I wanted to say that I'm using the DAZ skull and that I applied VSS to the skull and it really makes it look good. The red SSS gives the skull that sanguine, 'freshly peeled of flesh' look. Thanks you in advance!

If the puddle is thick enough, it can be totally opaque. In which case, there's not a lot of difference between a blood shader and an opaque glass shader. It's all about the shape. If you have the wrong shape, it won't be convincing.

So, go to my web site and get my Orb prop and shaders that come with it.

http://sites.google.com/site/bagginsbill/free-stuff/orbs

After installing that, load the first Orb shader, Orb001_Opaque.

After you load it, at the top left is a SimpleColor node. Change it to RGB 120, 0, 20 or something similar.

Make sure you have stuff to reflect all around, as the effect is largely about Fresnel reflection. I think you're using my EnvSphere already - that will work. An HDR image will work better than an LDR for that.

Here's TrekkieGrrrl's morphing puddle, done as specified above. Not the best shape, but the only puddle I have. I happened to be playing with Chris Cox's new bowling props so I threw in the puddle and rendered.

If you're using Poser Pro with render GC, you'll want to disable the shader GC.

Okay, I'll give it a go. I was using Trekkie's puddle but switched to another morphing puddle, however I have no idea where I found the prop. I am using the EnvSphere for reflection on the puddle and on an knife that is in the image.  I have an LDR image on it right now which might be why I'm not as happy as I could be with the reflection of the blade. This is what I have going so far.

Is that my shader? I can't see any reflection at all, even of the skull. Did you enable ray-tracing?

Also the blade should have a mirror shader. Set Diffuse_Value=0, Specular_Value=0, and put a Reflect node straight into Alternate_Diffuse. Turn off Reflect_Lite_Mult and Reflect_Kd_Mult.

This depends on your audience, of course, but bear in mind that for a lot of people, when they think of blood in large amounts, they're probably much more influenced by having seen it in movies; most people have never seen large puddles of human (or even animal) blood up close. For large amounts of blood in a movie, one of the most popular choices is still Kensington Gore, which is white corn syrup mixed with red (and a touch of blue) food coloring. In B&W movies, when it came up, they'd usually use anything dark; Alfred Hitchcock famously used chocolate syrup in the shower scene in Psycho. Some SFX artists use glycerin mixed with red creme makeup for close up, small amounts, and there are custom mixes you can buy from SFX and makeup houses.

My point here is that a lot of people will think it looks more realistic if it matches what they've seen in a movie than if it looks like actual blood.

That said, Arterial blood is going to be a bright red, whereas blood from a vein is going to be somewhat darker. You may want to swirl a little slightly darker red or reddish blue in the mix, to make it look like it came straight from the aorta and the vena cava together, or straight out of the heart. It also darkens fairly quickly as it sets up, and shrinks quite a bit as it dries. It's got a bunch of surface tension, so you'll want to the puddle edges to have a good curve to them, and it'll be just a touch thinner in the center, if it's free to spread out under its own weight.
 

No, BB, that little demo image had my old fresnal 'blood water' on it. After reading your suggestion, I applied your opaque orb shader to the puddle with the suggested color, then messed around for about a hour until I got a better shader for the metal on the dagger. I adjusted my lights. I dug up a HDRI image and placed on the Envsphere and did a preliminary render. This is my result. For some people raised on movies, my 'blood' might be too dark. But I await your opinions. I checked freestuff on that Dagger. It's called the Scorpion Dagger, and it's been in my P4 runtime forever, and I see that it's no longer in Freestuff. A shame, this is a great dagger. I'm not quite satisfied with the hilt texture. I used one of BB's wood shaders.

That looks great to me.

One thing that's troubling is the puddle seems to float above the floor. The spaces between the stones implies a dip there, but the puddle doesn't go down into the dip. I'd make the floor bricks have some displacement, so the blood is clearly in the grooves.

Yes, I wasn't sure what to do about that. The puddle is definitely on the floor. I'll try some displacement.

That's a very nive metal shader you have going on there.
Would you be open to sharing a pic of that setup for the knife metal?

Well, I'm in a bit of a quandry here DarkEdge. I have been using Poser since 1998 (Poser 3). I have textures, props, reflection maps for things that are no longer in Freestuff here, and for all I know, anywhere on the net. The reflection map I'm using seems to be one of those. I remember it was for a metal shader for P5, but I searched for it and it's no longer there. So, I can show you my node set up, but not the reflection map itself because I no longer have the original zip file and hence no readme so I'd have no idea about redistribution. I'll show you the shader using a reflection map I made. It won't give the same effect of course, and I'm sorry about that. If you search freestuff for reflection maps you'll find some packages there with something you might like.

Here you go.

I thought you said you were using the EnvSphere? In which case, the Reflect node will never consult the reflection map you have there. The EnvSphere is effectively your reflection map because it actually surrounds the scene.

The Sphere_Map node you have in the shader never gets called to simulate an environment sphere. You have a real one.

The blood seen in all the images so far looks too shiny and reflective to me. I don't think real blood is that reflective (not that I have ever bled that much).

Quote - The blood seen in all the images so far looks too shiny and reflective to me. I don't think real blood is that reflective (not that I have ever bled that much).

That could be. There is some different in reflectivity between glass and liquids, so using the glass shader may not give complete accuracy. But blood is pretty reflective, especially when viewed edge-on.

Using the glass shader is far more accurate than a naive reflective shader would be if it had no compensation for viewing angle. This is the Fresnel effect. I figured that using the glass shader might be a quick and good-enough tactic.

I could make another variation that uses the index of refraction for water instead of glass and this would have less reflection. But it would not be a lot less, just slightly less.

Quote - The blood seen in all the images so far looks too shiny and reflective to me. I don't think real blood is that reflective

I just gutted myseld Les, an no...it doesn't look very reflective. It's smells of beer though.

Thanks for the explaination Latexluv, no worries...always err on the side of caution.

Quote - I thought you said you were using the EnvSphere? In which case, the Reflect node will never consult the reflection map you have there. The EnvSphere is effectively your reflection map because it actually surrounds the scene.

The Sphere_Map node you have in the shader never gets called to simulate an environment sphere. You have a real one.

Okay, this I did not know. Then it's really the HDR image I chose for the EnvSphere that's doing all the work in the image.

I did some extensive googling for a photo of a puddle of blood. I had to skip past 28,000 photos of an item called the "blood puddle pillow". Apparently the Internet needs a lot of pictures of that.

I finally found a really gruesome photo from a slaughter house in the Middle East. Apparently they have this big one-day-a-year bloodfest where they kill animals a certain special way. Some tourist went around photographing the event  Anyway...

I carefully sampled the colors, built a reasonable approximation of the bumpy patterns the coagulating blood makes, and changed the reflection IOR to that of water, which seems to be close to right.

Here is my test render. I uploaded the material to my free stuff, random shaders area:

http://sites.google.com/site/bagginsbill/free-stuff/random-shaders

You'll find there a file called BloodPuddle.zip. It just contains the shader and a thumbnail. Install those in your materials runtime library and apply to the puddle.

It uses displacement and bump, so you want to enable displacement and ray-tracing for the full effect.

 

When viewed from a high angle, it reflects a lot less.

If you get down low, it reflects a lot more.

You might get artifacts like this at a low angle. Poser has issues with reflections on a surface that has displacement forming concave polygons. If that happens, just turn off the displacement. You may not really need or want it.

ithink it would be better to model the puddle and really have control how it looks in 3d.

That's very convincing blood, I'll certainly use it when I can drag myself away from my current pin-up phase!

Thanks bagginsbill, much appreciated.

That looks fantastic! Going to download that shader straight way.

Quote - ithink it would be better to model the puddle and really have control how it looks in 3d.

I agree - this free puddle is not ideal. But I'm not going to model anything. I'm the shader guy.

If somebody wants to model me a good puddle, and maybe some droplets with it, and give it away, that would be cool.

I had that dagger once too. I really miss it. It was such a great prop. I wonder where it went to. Great shader, BB. I'm going to try it on some flowing blood and see if I can make it work.
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