In this Tutorial I will show in easy to follow steps how to model a realistic looking rocket exhaustion using the graphics and animation software Blender.
Step 1: Create Rocket
Since I want to focus in this tutorial on the fire and smoke creation, I will just briefly go into the rocket modelling process.
- Be sure the 3d curser is in the center of the scene. Press
Shift + Sand Select Cursor to Center.
- The rocket will be created with a Cone as the starting point. Press
Shift + Ato open the Mesh Menu and select Cone. Change the vertices from 36 to 6.
Tip: It is in general good practice to start with a low poly count and increase later on, if needed.
- To bring the rocket into shape I have to extend the bottom part of the Cone. In Edit mode, select the lower ring of the Cone and press the
E Keyto Extrude the shape down.
- Now go to Face mode and select every other Face of the lower part. Under Pivot Point select Individual Origins, this is needed to extrude the wings out at once and not individually.
- To keep a good shape of the rocket first Inner Extrude the selected faces using the
I Keyand than press the
E Keyto Extrude the wings out. Finally move the extruded parts down using the Z axis (blue) handle.
- In order to smoothen the current low poly rocket shape I applied a Subdivision Surface Modifier. Click on the wrench icon in the Properties bar and select Subdivision Surface.
- Since the focus of this tutorial is the fire and smoke creation, I just added a simple exhaust to complete the rocket model. Let’s move on now to the fun part.
Domain and Flow – A short introduction
Before I continue with the Tutorial I think it is useful to give a brief introduction of what Domain and Flow mean. On Blender.org is a good explanation of the concept.
The bounding box of the object serves as the boundary of the simulation. All fluid objects must be in the domain. Fluid objects outside the domain will not bake.
So Basically we need a Box (Domain) that defines the boundaries of the fire and smoke simulation and in this case a Plane (flow) that defines the starting point of the fire / smoke simulation.
Step2: Add Domain
As we learned a domain (box) is needed that defines the boundaries. Since we want to have the fire/smoke simulation underneath the Rocket I started with adding a regular cube and placed it under the rocket.
- Place the 3d cursor under the rocket and press
Alt + Ato open the Mesh Menu, select the Cube.
- Size the cube using the
S Keyuntil you are happy with the shape.
- In order to transform the Cube into a domain (where the action will happen), go to the Physics tab under Properties select Smoke and than Domain. You will see now that the cube will get transparent and only the edge lines remain visible.
Step3: Add Flow:
Now that a domain is defined as the bounding box for the fire and smoke simulation, the next action is to create the flow (plane) where the fire is coming from.
Alt + Aand select a Plane. Size the plane (
S Key) and place it under the rocket exhaust within the domain.
- To assign flow to the plane go to the Properties Tab, than Physics – Smoke – Flow – Fire.
- If you press the Play button now you will see a flame going up as you would expect from fire and smoke. Since in our case however we need to the flame to flow downwards you need to change the following settings for the Flow Plane under Initial Velocity.
- Now rotate the Flow plane by 180 degree using the
R Keyso that the fire beam is pointing downwards. You can play with those values to increase the flame until you are happy with how it looks like.
Step4: Node Settings
The domain and flow related work is complete now but if you try and look how your model would look like at this point in rendered view (
Shift + Z) you would most likely just see a cube like this.
The reason why this is happening is Blender is assigning a default Material Shader to the domain but in this case we need a Volume Shader. More information on this can be found on the Blender.org site.
In order to make the flame and smoke visible in the rendered image we need to make changes to the domain node.
- Make sure the Domain Box is selected.
- Open the Node Editor.
- Make the following changes. You can add nodes using
Shift + AKeys.
- Back in 3D View, if you now press
Shift-Zthe box shouldn’t be visible anymore and you can see the rendered flames.
Note: The quality of the image is not high yet since we just use a few sample runs for this view. We are getting now to the actual Render setup.
Well done! The only thing left at this point is to add some light and render the scene. I just added a plane and a few Emission light sources. You can actually apply UV mapping and add textures to the rocket and ground. I will cover a tutorial on Rendering in a separate tutorial soon.