Getting Tattoos to go over seams is difficult, and sometimes they just look wrong. It can depend on the UV Maps the model is using, and the morphs the model has applied. This is the basic workflow to get a tattoo design anywhere onto the model you want it for.
The first step is getting your design in the right format. use quality .png designs with a blank alpha background.
Next you want to do some basic file setup. I've attached some blank 4k.png textures. Save them in a folder somewhere to use later.
With those in place, let's get started.
1. Open Vam and Load up the model you want the tattoo for.
Pay attention to what skin uv is loaded. Most looks with custom textures will use "Base Female". To change the uv set used, select a different skin in the skin select tab.
(for this example, I used the model in the demo scene, but I changed the skin to Base Female before exporting the obj)
Now that you have the model loaded and you are happy with what skin you want to use, you need to export an .obj
2. Export your model from vam with the ”Export OBJ and MTL files (Look in root folder after click” button on the "control and physics 1" tab. That will save an obj. in the root vam folder. We are done with Vam for now.
3. Open up Blender and import the .obj we just saved. Depending on your model and uv set, it will be named something different. Mine was named "female1-BaseF_skinned.obj".
(Remember that Vam will overwrite the exported model with the same name every time you click the button, so if you want to keep a specific model; rename it.)
It will probably be pink because blender can't see the texture files (don't worry about that for now.)
The model will be split into loads of material slot's because it uses the daz material layout, where the same texture is used for multiple regions.
To make things simple later lets setup some new textures to combine them into the Torso/Limbs/Face/Gens that Vam uses.
4. Select the obj and go into edit mode. You will see the mesh outlined with a black wireframe. Click on the screen somewhere that isn't over part of the model to make sure no faces are selected (selected faces will be highlighted in yellow)
We will first set up the limbs material.
A. Click on the "material properties" icon.B. In the materials list we need to selects all of the faces that are part of the limbs texture. For each one, click on the material from the list and then click on the select button. These are;
Legs
Toenails
Fingernails
Hands
Shoulders
Forearms
Feet
Remember to click the select button for each one to highlight the faces on the model. When they are all highlighted...
C. Add a new material with the plus icon and Name it "Limb Materials", then click the "Assign" button. That will assign the uv's from all of the selected faces to the new material.
D. Click somewhere in the edit window that is not over the model to clear all selected faces.
5. Repeat step 4 but selecting the torso texture faces;
Head
Neck
Hips
Torso
Nipples
Ears
Apply them to a new material called "Torso Materials"
6. Repeat step 4 but selecting the Face texture faces;
Nostrils
Lips
Face
Apply them to a new material called "Face Materials"
6. Repeat step 4 but selecting the Gens texture faces;
DefaultMat
Apply to a new material called "Gens Materials".
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Now to add the textures.
7. Select the Limbs Materials we just made and click on the "Shading Tab" at the top.
If you have custom skin textures and want to add them to the model, drag or open the diffuse limbs texture in here. Some base textures can be found in Custom/Atom/Person/Textures/Base Female.
Also drag or add the Limbs Decal Blank.png in the shading window.
We now need to add a mixRGB node from the list and arrange the textures like this to make anything painted on the decal texture appear over the base texture.
8. Do the same for the other material slots we made, putting the corresponding textures and decal in them too. Face/Torso/Limbs/Gens
9. Click on the Decal texture node so that it is highlighted white in all four material slots.
10. Click on the "Texture Painting" tab. You can now paint anywhere on the model and it will paint onto all of the decal textures that are selected.
Here is a youtube video that explains texture painting with a stencil brush in detail.
11. When you are done, save all of the decal textures for each material you edited with a new name. Remember to save them as .png, with the colour set to RGBA.
Now you can add them to your look in VAM. All of the seams will line up for the different decal slots.
You may want to do some cleanup in an image editor like gimp or photoshop. This is just the basic workflow. To get great looking tattoos you may want to blend them and adjust the alpha/colours etc. I went full black opaque text for this example, but you can get creative.
