RISA-3D to RISAFoundation: Getting Reliable Foundation Results

When you transfer a model from RISA-3D into RISAFoundation, you expect the reactions and design assumptions to carry over cleanly so foundations design the way you intended.
If the workflow is not set up correctly, you can end up with soil bearing pressures, uplift, or foundation failures that don’t match what you saw in your RISA-3D results—and it’s not always obvious where the mismatch is coming from.

This article walks through how the integration actually works, what transfers and what doesn’t, and a simple checklist you can follow to get reliable foundation results.

1. Understand What Transfers (and What Doesn’t)

RISAFoundation reads joint reactions organized by load category, not by load combination.
Those categories are defined in the Basic Load Cases spreadsheet in RISA-3D (DL, LL, WL, etc.).

What comes across:

• Reactions grouped by load category (DL, LL, WL, etc.)
• Supports defined as Reaction or Spring
• Wall reactions represented as a series of point loads along the wall base (based on the wall mesh)

What does not come across:

• Load combinations
• Fixed supports (these do not appear as foundations)
• Moving loads and non-linear/second-order effects on a per-combination basis

Model Settings come over only the first time you transfer. If you later change something in Model Settings that affects foundations, you’ll need to update it on the RISAFoundation side as well.

2. Set Up Load Categories Correctly in RISA-3D

If a basic load case doesn’t have a load category, its reactions will not transfer at all.
That’s one of the most common reasons for “missing” loads in RISAFoundation.

Before transferring:

• Open the Basic Load Cases spreadsheet
• Make sure every basic load case that should affect foundations has a category (DL, LL, WL, etc.)
• Save and re-solve the model so reactions are up to date

You also need to solve at least one single load combination before using the Director to move to RISAFoundation. That’s what generates the reactions that get grouped by category.

3. Check Supports and Global Axis

Next, look at how supports and axes are defined in the RISA-3D model.

• Any support that should generate a foundation load in RISAFoundation must be defined as Reaction or Spring
• Fully fixed supports will not transfer, so RISAFoundation won’t show a footing at those locations
• The global Y-axis must be vertical for the transfer to work. If Y is not vertical, you’ll get a warning when you try to move to RISAFoundation

It’s worth doing a quick visual check in RISA-3D to confirm that the supports you expect to see in RISAFoundation are defined correctly and located where you intend.

4. Transfer and Verify Loads in RISAFoundation

Once the model is solved and set up, use Director → RISAFoundation.

In RISAFoundation:

• The program opens with dead loads shown at supports in a plan view
• Use the load category dropdown (e.g., WL – Wind Load) to switch between categories and see how each one transferred
• Node labels will be different from RISA-3D but still comparable, so you can cross-check key reaction points

A good habit is to pick a few critical supports, compare the reactions in RISA-3D to the loads you see in RISAFoundation for the same category, and confirm they match within rounding.

5. Rebuild Load Combinations on the Foundation Side

RISAFoundation does not import load combinations from RISA-3D.
Instead, it takes the category-based reactions (DL, LL, WL, etc.) and applies its own combinations.

You’ll need to:

• Re-create your design combinations in RISAFoundation
• Optionally copy the combination spreadsheet from RISA-3D and re-enter the same factors and names

If foundation behavior doesn’t match what you expect, double-check that the combinations you built in RISAFoundation truly mirror the final set you used for superstructure design.

6. Handle Different Foundation Elevations Deliberately

If supports exist at multiple elevations (partial basements, podiums, adjacent structures), RISAFoundation will prompt you when you transfer:

• You can choose a single elevation if you only want true foundation reactions and need to ignore things like adjacent structure supports
• Or you can bring all reactions regardless of elevation if you actually have foundations at multiple levels

All elevations are mapped to a single plan elevation in RISAFoundation for design, so it’s important to think about how you want to represent stepped foundations or partial basements.

Conclusion

For routine building projects, the category-based reactions are usually sufficient. For heavily non-linear or stability-critical systems, supplement the automatic transfer with targeted hand checks or additional manual load cases for critical foundations.