Rawfile format

The format of the files written by spice -b -r, the write command and run file, and read by the load command.

A rawfile holds one or more plots, one after another. Each plot is a text header followed by its data, which is either text (Values:) or binary (Binary:). The filetype variable chooses between them (ascii or binary); the default comes from SPICE_ASCIIRAWFILE.

Title: the circuit's title line
Date: date and time of the run
Plotname: e.g. Transient Analysis
Flags: real | complex [unpadded]
No. Variables: n
No. Points: points
Dimensions: d1,d2,...             (only for multi-dimensional plots)
Command: a command                 (any number)
Option: name [= value]            (any number)
Variables:
	0	name	type	[attributes]
	1	name	type	[attributes]
	...

Flags: complex if any vector is complex (as in an ac analysis), otherwise real. unpadded means shorter vectors stop at their own length instead of being padded with zeros to the length of the longest; the nopadding variable writes unpadded files.
No. Points: The length of the longest vector.
Dimensions: The dimensions of the longest vector, when it has more than one (as in the merged plot of a .step run).
Command: A command run when the plot is loaded.
Option: A variable setting saved with the plot.
Variables: One line per vector: its index, name and type (time, frequency, voltage, current and so on), optionally followed by min=, max=, color=, scale=, grid=, plot= and dims= attributes. The first vector is the plot's scale.

Header keywords are not case sensitive when a file is read.

Text data

Values:
0		value of vector 0
	value of vector 1
	...
1		value of vector 0
	...

For each point, the point number is followed by the value of each vector in turn, one per line, indented with a tab. Values are written in %e format with 15 digits after the decimal point, or as many as the rawfileprec variable gives. In a complex plot every value is written as real,imaginary.

For example, the header of the ac results of examples/meas_demo.cir, written by spice -b -r:

Title: meas_demo.cir - .meas on an RC low pass: tau = 1us, corner 159Hz
Date: Mon Sep 28 15:18:28  2026
Plotname: AC Analysis
Flags: complex
No. Variables: 7
No. Points: 401
Command: version 3f5
Variables:
	0	frequency	frequency	grid=3
	1	V(1)	voltage
	2	V(2)	voltage
	3	V(10)	voltage
	4	V(11)	voltage
	5	va#branch	current
	6	vin#branch	current
Values:
...

Binary data

Binary:
point 0: a double for each vector
point 1: ...

After the Binary: line, the data follows directly as native double values: for each point, one value per vector in turn. In a complex plot each value is two doubles, real then imaginary. Binary files are smaller and faster to read, but are only portable between machines with the same floating-point format and byte order; use text files to move data between machines, or to edit it.