So you can see my problem here:
(https://www.sc4devotion.com/forums/proxy.php?request=http%3A%2F%2Fglidingeagle.com%2Fimages%2Fsc4%2Fsc4walls.jpg&hash=a71d3c232879d38cc70b3cc1caa4da3ec3f6cdc0)
The walls are a base a texture, and so is that grunge concrete. What is the best way and tool to replace the grass with the concrete ?
In this case, you can simply use the Grunge Concrete Extenders which would overhang the grass. I guess there is no space for that, but if you open the original lot in LE and duplicate the overhanging prop the other way round, you can save it as a unique lot (Save As) so you've a copy which overhangs in four directions.
If you wanted to make the texture, place both textures on separate layers. Remove half of the top one and you'll either get grass on your concrete or concrete where the grass is now.
You can do this pretty easily with Photoshop or GIMP. Like mgb204 said, place them on separate layers, then use a layer mask to mask out half of the top layer. (You can use a guide to do this precisely - since Photoshop doesn't support diagonal guides, I find it easiest to rotate both textures 45 degrees, cut them, then rotate them back.) It's probably not what you need here, but if they're similar textures, you can also use a gradient on the layer mask to make a smooth transition:
(https://www.sc4devotion.com/forums/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FJVrQynw.png&hash=b130a31a520ad1af50c506fecb64c5556333e935)
I think that there's a much easier way, if Kitsune can live with creating an overlay texture containing the grungy concrete as a diagonal only:
1. Open MS Paint and create a picture with the size of 128x128 pixels where one diagonal side is entirely black and the other entirely white. Make sure that this picture only contains white, black, and grey (for any shade of grey, the values for Red, Green, and Blue are exactly the same). This picture will be your alpha map.
2. Use SC4Tool to create a new overlay texture, applying the grungy concrete in the top half of the screen and your diagonal alpha map on the lower half of the screen.
This way, you can make a grungy concrete overlay texture where one diagonal side is transparent, and place it over the other base texture in LE to create a new lot.
BTW: Where did you get that retaining wall lots (the mossy concrete one)? I'd like to have it, if possible.
These ones I believe: http://sc4devotion.com/csxlex/lex_filedesc.php?lotGET=131. Be warned... the underbridge is for L2 only. And its what I feared.. GIMP. I sketch.. write.. but GIMP ? One of my few enemies in life :D
As I said, why bother with a texture at all? I've attached a lot with the overhanging prop duplicated and rotated 180 degrees. Find this above the original double-diagonal lot.
I got memory issues and forgot about your post ! :D