The collision works but if you stand on it and place the same block connecting to it the collision is gone for a second letting the player fall through

 

 

 

heres my code

package com.linumhost.Blocks;

import java.util.Random;

import org.lwjgl.opengl.GL11;

import com.linumhost.CreativeTab.ServerCreativeTab;
import com.linumhost.Items.Items;
import com.linumhost.Items.Wrench;
import com.linumhost.Renderer.BasicRenderer;
import com.linumhost.TileEntity.TileEntityConduitPipe;
import com.linumhost.TileEntity.TileEntityServerCaseBlock;
import com.linumhost.TileEntity.Renderer.TileEntityConduitPipeRenderer;
import com.linumhost.lib.RefStrings;

import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;
import net.minecraft.block.Block;
import net.minecraft.block.BlockContainer;
import net.minecraft.block.material.Material;
import net.minecraft.client.Minecraft;
import net.minecraft.client.gui.FontRenderer;
import net.minecraft.client.renderer.entity.RenderItem;
import net.minecraft.client.renderer.texture.IIconRegister;
import net.minecraft.entity.EntityLivingBase;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.tileentity.TileEntity;
import net.minecraft.util.AxisAlignedBB;
import net.minecraft.util.IIcon;
import net.minecraft.util.MathHelper;
import net.minecraft.world.IBlockAccess;
import net.minecraft.world.World;
import net.minecraftforge.client.IItemRenderer.ItemRenderType;
import net.minecraftforge.client.IItemRenderer.ItemRendererHelper;

public class ConduitPipe extends BlockContainer{

public ConduitPipe(Material material){
	super(material);
	setCreativeTab(ServerCreativeTab.tabBlocks);

	float pixel = 1F/16F;
	this.setBlockBounds(11*pixel/2, 11*pixel/2, 11*pixel/2, 1-11*pixel/2, 1-11*pixel/2, 1-11*pixel/2);
}



    private static RenderItem renderItem = new RenderItem();

    public boolean handleRenderType(ItemStack itemStack, ItemRenderType type) {
            return type == ItemRenderType.INVENTORY;
    }

    public boolean shouldUseRenderHelper(ItemRenderType type, ItemStack item, ItemRendererHelper helper) {
            return false;
    }

    
    public void renderItem(ItemRenderType type, ItemStack itemStack, Object... data) {
            FontRenderer fontRenderer = Minecraft.getMinecraft().fontRenderer;
            
            // ====================== Render item texture ======================
            IIcon icon = itemStack.getIconIndex();
            renderItem.renderIcon(0, 0, icon, 16, 16);
            
            // ====================== Render OpenGL square shape ======================
           
            BasicRenderer.drawInventoryBlock();
            
            // ====================== Render text ======================
            GL11.glEnable(GL11.GL_TEXTURE_2D);
            String text = Integer.toString(itemStack.getItemDamage());
            fontRenderer.drawStringWithShadow(text, 1, 1, 0xFFFFFF);
    }



public AxisAlignedBB getSelectedBoundingBoxFromPool(World world, int x, int y, int z){
	TileEntityConduitPipe conduit = (TileEntityConduitPipe)world.getTileEntity(x, y, z);

	float pixel = 1F / 16F;

	if(conduit != null){

		float minX = 11*pixel/2-(conduit.connections[5]!=null?(11*pixel/2):0);
		float minY = 11*pixel/2-(conduit.connections[1]!=null?(11*pixel/2):0);
		float minZ = 11*pixel/2-(conduit.connections[2]!=null?(11*pixel/2):0);

		float maxX = 1-11*pixel/2+(conduit.connections[3]!=null?(11*pixel/2):0);
		float maxY = 1-11*pixel/2+(conduit.connections[0]!=null?(11*pixel/2):0);
		float maxZ = 1-11*pixel/2+(conduit.connections[4]!=null?(11*pixel/2):0);

		this.setBlockBounds(minX, minY, minZ, maxX, maxY, maxZ);

	}
	return AxisAlignedBB.getBoundingBox(x+this.minX, y+this.minY, z+this.minZ, x+this.maxX, y+this.maxY, z+this.maxZ);

}

float pixel = 1F / 16F;

public int getRenderType(){
	return -1;
}

public Block blockDropped(int par1, int y, int par3)
    {
        return com.linumhost.Blocks.Blocks.conduit;
    }

public boolean isOpaqueCube(){
	return false;
}

public boolean renderAsNormalBlock(){
	return false;
}
@Override
public TileEntity createNewTileEntity(World p_149915_1_, int p_149915_2_) {
	return new TileEntityConduitPipe();
}


}

Follow this tutorial,

it should help you on pipes.

 

Also from what I see you need to implement the getCollisionBoundingBoxFromPool() to set your custom collisions.

 

Also add @Override on top of Override methods

 

getCollisionBoundingBoxFromPool() and getCollisionBoundingBoxFromPool() are both overridden methods.

Follow this tutorial,

 

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