Migrating from Tidy3D

This page covers migration and compatibility with Tidy3D.

Flexcompute RF (also Flex RF) was historically developed as an extension to the Tidy3D photonics solver. In early 2026, all of the RF-related features in Tidy3D was migrated to the Flex RF package as a standalone product.

Note

All RF-related development will continue in the Flex RF package only. RF features in Tidy3D will continue to remain available to RF-licensed users in the short-term, but they will become stagnant and support is no longer guaranteed. It is also possible that RF features will be completely removed from Tidy3D in the future.

For users migrating from Tidy3D, the first step is to change the import statements and consolidating the namespace prefixes.

# OLD (Tidy3D 2.11)
import tidy3d as td
import tidy3d.rf as rf
import tidy3d.web as web

# NEW (Flex RF)
import flex_rf.tidy3d as rf
import flex_rf.web as web

# Search and replace 'td.' with 'rf.' in the rest of the project

Why flex_rf.tidy3d?

During this transition period, we will use the flex_rf.tidy3d namespace to indicate that many components are shared with Tidy3D. Official migration to the flex_rf namespace will occur in a future update.

The FastDispersionFitter can now be used directly without a separate import statement.

# OLD (Tidy3D 2.11)
from tidy3d.plugins.dispersion import FastDispersionFitter
my_lossy_dielectric = FastDispersionFitter.constant_loss_tangent_model(...)

# NEW (Flex RF)
# No need to import separately
my_lossy_dielectric = rf.FastDispersionFitter.constant_loss_tangent_model(...)