Texturing is something very hard, don’t be ashamed if your texturing is not of high quality.
To be honest i think it’s even harder than modelling if you want to get something that actually looks good and it’s very easy to get something that look very bad.
But to give you something to start with , here’s something very basic
I don’t know if you have photoshop, as the full version of photoshop CS2 is oddly freely and publicly downloadable on adobe own website :
So i’ll take GIMP as an example.
First in Blender. that’s not very good to have ngons on something you’re going to unwrap, it’s never good on anything you intent as a game asset (and check your polycount, the subsurf you added to the barrel with holes skyrocket the polycount).
Select all those faces (in face selection mode), press X -> Dissolve, then press F6 and enable “Dissolve Verts” to obtain this :
Then add a loop cut (CTRL+R) there :
And select those vertices
Press J to join them in an edge
That’s all for this section, it’s now all quads .
Now press U -> Unwrap
By default, the unwrapping is in angle based, but as it’s not something organic, we want the unwrap to be in conformal mode, so after having done the U->Unwrap press F6 and change the method from Angle Based to Conformal.
Now in the UV Editor click on UV -> Export UV as Layout.
Save the png file where you want , notice the size you’re saving it (in the Save window, look into the panel to left, at the bottom), by default it’s 1024x1024 i think.
Now open Gimp
Load your png layout
In the layer tab, right click and select “Add a New Layer”
Move that new layer on the bottom, so the uv layout is always on top
Make sure that new layer is selected
Fill that layer with some dark grey
Make sure the new layer is selected then click now on Filter -> HSV noise
In the popup set Saturation to 0 , increase Value to +/- 30 and click OK
Right click on that Layer and select “Duplicate Layer”
For the layer that is just under the top layer set the mode to “Overlay” and set the opacity to +/- 70
Now select the layer that is at the bottom
Now click on Filter -> Blur -> Motion Blur.
At the popup set Angle to 0 and length to 50 then click OK
That should give something very roughly metal-like (see some tutorial on google on how to get something better than this as it’s just something basic, or just download a free metal texture if you wish)
Add another new layer, make sure it is full of transparency, move it on top of both the grey layers, but again under the uv layout layer.
We’ll now work on it, select your brush tool and set its color to black and draw a line (to draw a line in gimp, click once with the brush somewhere, then hold shift then click at the destination of that line).
By example , following the UV, i draw like this (lower a bit the opacity of the UV layout layer so you see what you are doing, but be sure to reselect the correct layer to draw on, because in the end we will delete the UV layout layer) :
Now change color of the brush to white, and draw along the black lines with it so we get some kind of depth effect
Now change this layer mode to Overlay too, so it “imprint” more nicely to the background
That will be all for this simple example, texturing involves more than lines but lot more work, but that’s a basic way to start, lines on hard surfaces usually helps to gives some “panel” feel that increase nicely the texture visual, don’t understimate the power of lines
Delete now the UV layout layer and right click on the layers -> flatten the image
Save this image into a new texture, and load it in Blender
More work to do on the texture (dust, scratches, reflections, shadows, etc…) , but it’s a good basic for what is the workflow regarding layers, layers modes etc…
By example trying to add some scratches (low size brush strokes, playing with the brush and layer opacities etc…)
It’s where it is good to have the uv layout as a layer, as it is usefull as a guide to where add some brush strokes etc…