After digging through the native sided textures for a while I tried this:

{
"parent": "block/cube_all",
"textures": {
	"side": "technica:blocks/rubberlogSide",
	"top": "technica:blocks/rubberlogTop"
}
}

 

Shouldn't this cause the textures of my block to be sided?

The block is called "rubbertreeLog" btw.

take a look at the log json, u should find it quite interesting

I am not extending the rotated pillar / blockLog classes, since I need some extra functionality. At the time being by block class simply extends Block.class

When using "all": it displays the correct texture.

i never said u need to extend that, i just told you take a look how vanilla does. look at the log.json (i think it was that im not sure and got no ide here) , you will find how it is done there.

since the log.json should be rather complicated because it is a "rotated pillar" I took a look at bookshelf.json. Which is basically what I want. It has a texture on its sides and on on its end. And it worked.

For anyone looking at this:

When making a sided block cant use "block/cube_all" you have to use cube_column (in my case) or others.

The json file also has to be FLAWLESS

using the wrong texture name will cause the whole model to break. Errors in json code as well.