The Fire source tool allows you to place a fire source on the scene.
You can place the fire source on the horizontal surface of any object which has a defined value of the Material property: solid object, wall, floor slab, landing. You cannot place a fire source on the object made of non-combustible materials. For details, see Material and Substance Editor.
To activate the Fire source tool, click the 
button or use the Alt + G hot key.
In Fenix+ 3 applicatopn, you can place a fire source in one of two ways:
- Create a fire source automatically with the maximum area in the shape of a rectangle;
- Create a fire source manually in the arbitrary shape of the desired size.
To place a fire source automatically, do the following:
- Click the
button. - Press the LMB on the desired object on the scene.
As a result, the application automatically creates a fire source of the maximum size and rectangular shape on the surface of the object.
To place а fire source manually, do the following:
- Click the
button. - Place the mouse pointer at the starting point of the required area on the desired object.
- Press and hold the LMB and move the mouse pointer to construct the required area.
- Release the LMB to complete the area construction.
As a result, a fire source of the desired size and rectangular shape is constructed on the surface of the selected object.
If the maximum burning area differs from the area of the fire source, select the fire source using the Pointer 
tool, check the box next to the Specify maximum burning area parameter, and enter the required value in the Maximum burning area field. In this case, the fire source will burn entirely, rather than igniting from a point. The burning power increases according to a quadratic law from zero to the maximum value that a fire source with the area specified in the Maximum burning area field can have. The law of power increase correspondes to the circular fire spread with the linear flame spread rate relevant to the selected material.
If the Flame spread to lateral surfaces property is activated in the fire dynamics simulation parameters, then along with the top surface of the fire source, the lateral surfaces also burn, but the above-described law of increasing the burning power of the fire source remains (in total across all surfaces). For details, see Setting Parameters for Fire Dynamics Simulation.
The combustible properties of the fire source are determined automatically on the basis of the object material on which the fire source is located, as well as the size of the fire source area.
There are two possible fire development scenarios:
- Circular distribution from the center of the fire source;
- A fire occurs immediately across the entire indicated area.
The fire distribution is determined by the linear speed of the spreading flame through the material of the object on which the fire source is located. If the flame spreading speed equals to zero, then the fire occurs immediately across the entire indicated area. If the flame spreading speed is not equal to zero, then the fire is spread in the circular way.
If the fire is spread in the circular way, then the fire is distributed from the center of the fire source.