Side texture blend blocks (ice, glass like)

ULTIMATE 1.12.2 SOLUTION 

Here's how to do it in 2020.2 - 1.12.2 minecraft forge in mcreator...
Cause pylo (suck), and dropped 1.12.2, there's a couple of us still keeping it alive, cause 1.12.2 are "the best" no argument please.

For anyone else who came across this page at random, Trying to findout how to do this Broken thing in mcreator, in the only 1.12.2 supported version left that actually Functions like it's meant to (i'm lookin at you 1.12.2 plugin 🤮)

1. If you're using a custom model, In Blockbench or etc, Cull your faces, you can do this via right clicking each face's texture view and selecting their correct culling option. Otherwise ignore this step
2. Set your block to your appropriate transparency setting, you should have already set this up.
3. Make sure you have your block Just as you Want It, before you lock the code and manually edit it. You will sadly need to do this.
( not very fun fact : if you make something in a procedure at this point, that runs off the block and changes a dependency or etc, you will need to unlock the code and do this entire step again )
4. Go into the code after you locked it (the java class), Press Ctrl+F and type in "BlockRenderLayer", You should be able to find where it defines the general transparency of your block.

5. Somewhere after this area of the code (mentioned in step 4.) or in that general area. enter the Following...

		//edit start

	    public boolean isFullCube(IBlockState state)
    	{
        return false;
    	}

       @SideOnly(Side.CLIENT)
 	   public boolean shouldSideBeRendered(IBlockState blockState, IBlockAccess blockAccess, BlockPos pos, EnumFacing side) {
        IBlockState iblockstate = blockAccess.getBlockState(pos.offset(side));
        Block block = iblockstate.getBlock();

   	   return block != this && super.shouldSideBeRendered(blockState, blockAccess, pos, side);
    	}

     @Override
    public boolean canRenderInLayer(IBlockState state, BlockRenderLayer layer) {
        return layer == BlockRenderLayer.CUTOUT;
    }

//edit end

(sorry for my messy copy-paste)
If you ever need to unlock the block, recompile it and then add this back,
You can always Ctrl+F the "edit start" message i added :)

6. Add "
import net.minecraft.util.EnumFacing;
" As an Import at the start of the code. You can space it out so you know where you added it if you want,
With Shift+Enter, These are basic text formatting skills that i think you should already know.

if you're Also a 1.12.2 mod maker who uses mcreator and tries to push the limits of what mcreator can do..
Feel free to join my dis cord ser ver i made, that has a Very Helpful channel in it, dedicated to random fixes and solutions for things Like This i have found and fixed with the help of others and countless annoying debugging ventures.

Pylo doesn't care, But doesn't mean i won't do it.

Well, if you brought back some sort of 1.12.2 support, Instead of catering to the thing of "Ah yes, The latest version is what Everyone Wants", That'd endup being a better decision anyway.
He ck, as-is the main modding versions are 1.6, 1.7.10, 1.12.2 and 1.14.4
If you Mainly focused on support for features for those; other versions and built up More Consistent framework for features, with simple edits on how it would Compile per version instead of using your own sc uf fe d block extension and etc, You​ would endup with that All-Version Mcreator of our dreams.
I don't know cr ap about java besides what i've learned so far over the years, messing with your tool..
But one thing i Do Know, Is how to have Consistent development and quality control.

I'd suggest something like, Focusing on adding More Advanced Features to mcreator; and allowing people to have More Freedom over what they can do. Generally marketing it to a older group of people and such.

You could easily avoid the entire issue of... People using mcreator to... make horrible mods that make the tool be discredited 
And it's not an issue of "Well why do visual based stuff and node based stuff when you can do real java and mod",
As.. Visual based stuff like this has So Much Potential, And Nobody is treating it seriously, besides stuff like The Unreal Engine.

I know you don't have much free time but.. I hope there will be a day where the potential of this Tool is met, and us users who use Mcreator to create Fun and Enjoyable mods, will have a better time too..

PS -
also, ngl.. It sorta sucks to be using such an outdated, unsupported, tr ash version of this program lol,
Every day i need to Literally Manually fix the entire gradle, as it explodes all the time,
I constantly encounter bugs that will never be fixed..
And it's not like i can use your Plugin,
As it's Also not a main focus, isn't supported, is just for "archive sake" or whatever,
Half of the features in 2020.2 are bugged with it, and it compiles broken code sometimes - breaks the gradle MORE then 2020.2

I know i've said this a lot over my time on this site 'n using your tool,
But.. What else can i do lol,
This is a passion of mine, and this is my main way of expressing that.

Understandable.
But sadly, there is a difference between adding Plugin Support and actually Giving Support to a version.
The 1.12.2 compiler we Have right now, Is only 2 options.
one being an outdated version that is dead, and the other being a plugin that is almost Dysfunctional as it works Worse.

This issue wouldn't even exist, if you treated this program with more respect then letting it be a side project - letting the community deal with it, when the Community you have built, is mainly orientated around Children who don't know how to Make Mods in the first place. As-is, You have a major community going on here, But only a couple people have actually made Plugins.
I'm not gonna fix your program for you, and neither do I know How.
And neither should you expect me to.. Us to.
As its creator, That falls upon you.
Hopefully this has given you a differant perspective to think upon. 

You do understand that the entirely of this community you've built up around your program,
Is Literally Built around people who don't know how to make mods in java, and then Use Your tool for that...
And asking your community to do work like this for you is disproportionate and dumb.
As they don't Know How to Help you; and this has made sure of that.
If you marketed your Tool as a development Assistent or etc more then a Instant Mod Maker for children, Or gave it more of a side For That, This would be fine.
But you didn't, and haven't

Well,  Neither did notch.