Box dropper

In this tutorial, the procedure of creating a box dropping device will be shown. The box dropping device will create a new box whenever the old one is destroyed.

Creating the device

In this part, the design, the looks of the dropper will be created.

They should look like this.

Step 1

For creating the tube for the standard box dropper, props will be used, which will eventually form a box transportation tube.
Create two prop_dynamics. The first one's world model is models/props/box_dropper.mdl. Set the second one's name to box_dropper_cover and set its world model to models/props/box_dropper_cover.mdl. Now, move the two models to that the second one is at the bottom of the first one. Refer to the screenshot for placement picture.

A long way down.

Step 2

Note:This step is optional. You may change most of the textures mentioned in this step - they are only used as an example.

First, create a brush with the sizes 128x128x16 (width x length x height) These sizes are optimized for the size of the tube prop and the cube. This is going to be a part of the ceiling of your room and where the cube enters the room. Create a cylinder with 8 sides, with the size of 88x88x16, and place it in the center of the previously created brush and carve it. Now delete the cylinder and select the 8 brushes the carving created. Tie these to a func_detail entity.

Note:You might have to shrink the grid to the size of 4 to do this.

Create 2 128x16x128 and 2 16x128x128 brushes. This is going to be the bottom part of the long corridor down. Use these four brushes to create a corridor. Put a metal/metalwall048c texture on the inner face and tools/nodraw on the outer faces of each brush.

Helping the cube down.

Create 2 128x16x256 and 2 16x128x256 brushes and place them together on top of the previous brushes. Texture them exactly the same way except that the inner faces should have a the texture metal/metalwall048c_gradient. Shift these textures so that the orange ends are on the top and the black ends are on the bottom of the faces.
To seal this hole, create a 128x128x16 brush and place it on top of the corridor. The inner face's texture is lights/light_orange001 and the outer faces' texture is tools/nodraw.
Additionally, you may want to place extra brushes textured with tools/nodraw on top of the bottom piece to ensure that the box will fall down into the tube. Make sure all these brushes are tied to a func_detail entity. Refer to picture 3.
Finally, place the two models which you created in the previous step so that the cube falls through the cylinder right into the tube.

Creating the dropper

In this part of the tutorial, the triggers behind the dropper are created.

Note:This part of the tutorial assumes that you did not skip Step 2 of the last part.

The weighted sealed room.

Step 1

Create a sealed room seperately from any other part of the world. This sealed room should be a cube sealed by six brushes with each face of each brush textured with tools/nodraw. Inside this sealed room, place a prop_physics with the name template_box and the world model models/props/metal_box.mdl. Additionally, you may change the Skin keyvalue of this prop to 1, in which case the cube will look like a weighted companion cube.
In this very same sealed room, create a point_template. Set the name field to template_box_drop and the Template 1 field to template_box. This entity will assist in creating a new box whenever required.

Step 2

Place an env_entity_maker entity in the center of the long way down, about 48 units below the top piece. Set its name to box_maker and the Point_template to spawn field to template_box_drop. Hang in there. It's almost done.
The final piece of the puzzle which controls the whole mess and forms it into a box dropper. Create a logic_relay entity anywhere near the contraption and name it logic_drop_box. Add three outputs.

Output named	Target entities	Via this input	Parameter	Delay
OnTrigger	box_dropper_cover	SetAnimation	open	0.00
OnTrigger	box_dropper_cover	SetAnimation	close	2.00
OnTrigger	box_maker	ForceSpawn		2.00

How it works

Cubes can be detected by creating a filter_activator_name with the Filter name field set to the same string as your box template - in this tutorial, it is template_box. Set it's name to, for example, filter_box. Create a trigger_multiple with the filter field set to filter_box to check whether the box is in a place you don't want it to be (for example acid). Add two outputs to this trigger.

Output named	Target entities	Via this input	Parameter	Delay
OnStartTouch	!activator	Kill		0.00
OnStartTouch	logic_drop_box	Trigger		0.00

Additionally, you can disable the recreation of the box when, for example, you destroy the box permanently. This is done by sending a Disable input to the logic_drop_box entity.
This concludes the tutorial.