Blender Beginner for Beginner Tutorial: Mech Model Part 2: Texturing
5th June 2010 – Blender 2.47
Having created a basic low-poly mecha model in a previous tutorial, it is now time to liven up the model by texturing it. The application of materials and textures is the hardest part of modelling for me, and I’m not entirely happy with the result. My artistic abilities need some work. However, the general technique is still worth noting. The tutorial will show how the mech model was made to look as below. Later tutorials will show how to rig the model and animate a walk cycle.
UPDATE: I have discovered since writing this tutorial I have textured the mech in completely the wrong way for importing it into game engines. Instead of having multiple materials for the mesh and textures applied to just a few faces, there should be a single material for the entire mesh and textures should be images applied to all the faces. Also normal maps should not be black and white, but a special colour scheme. See the spaceship tutorial for a better way of texturing if the goal is using your model in a game.
- Start by setting the base material for the model which will be green hard matte plastic (later a simple camouflage texture will be applied). On the Link and Materials subpanel of the Editing (F9) panel, create a new material by clicking the New button under the material selector. By default this first material will apply to all faces. This is fine for now. On the Shading (F5) panel set the colour of the new material to a medium green, (R,G,B) at (0.316, 0.614, 0.267). Then set the specularity and mirror colours to pale greens, say (0.77, 0.98, 0.72). This will be the reflected colour which should be very similar to the base colour. Use an Oren-Nayer Shader as it is good with matte surfaces. I set the reflection down to 0.6 (as the material is matte and doesn’t reflect too much) and the roughness very low at 0.5. Use Blinn (as it works well with Oren-Nayer) for specular highlights with Spec lowered to 0.2 so the light reflected is quite low, but there is still some. Set the hardness way down at 1 to make the specular highlights diffuse (that is the edge of light reflecting off the model should not be sharp).
- Next apply a camouflage pattern. Create 2 textures using the Textures panel. One should be a Stucci texture with noise size 0.1, turbulence 5 which becomes the camo detail. The other will be a noise texture for dirt.
Map them both orco (on the Map Input subpanel of the Materials panel) and have both only affect colour. The camo texture should be a dark green and greatly change the colour (set to 1 using the Col slider on the Map To subpanel, see the image below), the dirt should be black and only slightly change the colour (the Col slider should be 0.2). This should complete the camo base, although you could add a third colour (perhaps black) with another Stucci texture to the current 2-colour camo if you desire.
When creating new materials, Blender will by default copy the previous material (or at least the one displayed in the material selector when new is pressed). So next create those materials with the same camo texture as the base material to save having to recreate it later. Firstly a unit number will be placed on the top of the mech. In the image editing program of your choice (I used The Gimp) create an image with the unit number and ensure the background is transparent. If it isn’t transparent (and a white background is used) then it will affect the colour of the whole area to which the image is appiled (for a white background this would make the green paler), not just the bit you want to add. The image I created and used is here. It will help if in the next step there is a UV window open. This displays how any image texture will be applied to the selected faces. RMB on the join between the 3D view window and the panel window. Select Split window and size a small window. Then using the Window Type selector (usually in the bottom left corner of each window), select UV Image Editor type. Select the top four faces of the mech like the left image, unwrap (with U KEY) like the right image below and create a new material just for these faces (create a new material, then click assign to make it applied to just the selected faces).
The four faces shown in the UV window are projections of the 3D faces on the mech onto the 2D of a texture image. The grid behind the faces will be the texture image. So it is possible to arrange the faces in any way over the image. For now leave them as they are. At this point there will be no discernable difference to the mech, as the new material is a copy of the base material. Add a new image texture and load the 74.png image. Set it to Clip using the clip button on the Map Image subpanel of the Texture panel. This means if the image doesn’t take up all the faces of the material, the image will not be stretched to fit, the remaining area will just not have the image applied. Repeat would repeat the image texture. Extend would stretch the edge of the image to the edge of the faces – since the edge of the unit number image is transparent this will look the same as clipping. On the Map Input subpanel of the Material panel use UV mapping (with the UV button) to have the image applied to the faces according to the layout of the UV window. On the Map To subpanel set it only affect the colour. Thus the unit number is now painted on top of the mech as shown below. I followed the same process to apply the number to the left side of the back of the body of the mech.
- In a similar manner to the previous step the hatch image was applied to the right side of the back panel of the mech. The warning image was applied to the join between the head and legs and arrow images to the outside of each knee (so you know which way is forward!). Scale, rotate and move the UV unwraps to get the images in the right place for the faces selected. The faces may extend beyond the texture image to make the image appear smaller than the faces (useful for the arrows). Remember to set the image textures to clip. Also a good tip to see if you have the right faces selected for your material is after creating the material and assigning faces, deselect all faces and use the select button under “Link and Materials” to see what Blender thinks the faces for the material should be.
- UPDATE: The below is the wrong way to affect normals – normal maps should not be black and white, but a special colour scheme. See the spaceship tutorial for a better way of texturing if the goal is using your model in a game.
The face panels of the mech will be a sensor mesh. To that end I created a sensor mesh image. Select the faces and assign them a new material. Also do a UV unwrap with a cube projection and scale them to fit within an applied image (that is the faces all fit inside the UV grid) – this is so the image is applied to all the faces.
It took me a few attempts to get the UV unwrapping looking right when the image texture was applied. Try the different unwrapping systems, see how the result looks and try to work out why. Create a new image texture and load the sensor mesh image. It is a photo negative of the actual mesh. This is so that the single image can be applied to both the colour and normals – as colour can be reverse applied like normals (but not the other way around) and I wanted the mesh to appear sunken into the body of the mech. Delete the camo textures. Have the image use UV mapping (on Map Input) and affect colour (0.4 as I still wanted the green to show through) and normals (10, to make the mesh show through strongly).
- As a last little feature let’s place a little laser bud on the nose. Select just the nose faces. Create two textures: the first a sphere blend texture (applied to the normals only); and a little red dot image applied to both normal and colour.
- Now pack the textures into the blend file. Go to File → External Data → Make All Paths Relative, then File → External Data → Pack into .blend file. This loads the image files used for textures on the model into the blender save file itself, so that the blend file contains everything necessary to display the model and the images don’t have to be distributed separately. This last step is not necessary, but I have performed it on the blend file that can be downloaded as an example.
You can download the blend file here. The next stage is to rig the mech for animation and the tutorial for that is available here.
Mech Texture Blender Model by Charles Cordingley is licensed under a Creative Commons Attribution 2.0 UK: England & Wales License.