3D model
Parts without material or with Generic.
If no material is chosen in the CAD package, a default such as Generic, Default or Steel is often filled in. The weight is then wrong, the purchase line cannot be carried out and the drawing says something different from the model.
Published 21 September 2026
01 What it is
No or default material, briefly explained.
A material is missing if no material has been assigned to the part in the CAD package. Usually the package then fills in something itself: Generic, Default, or a general steel grade without designation.
That is something different from a STEP without materials. Some exports do not include material data at all; then there is nothing to check in the model and you have to do it on the drawing and the BOM.
How you notice it
- The calculated weight deviates from the actual weight
- The drawing states a material that does not occur anywhere in the model
- Purchasing calls back about a line without a specification
- Some of the parts have a material and some do not
In a check
This shows up as caution in the check of the 3D model. You judge what has to be done about it.
02 Example
What it looks like.
Example design GRP-2210 (demo)
- Parts with material
- 38 of 46
- Without material
- 5 parts
- Default value Generic
- 3 parts
- On the drawing
- S235JR
Because most of the parts do have a material, it stands out that the rest is not filled in. If there is no material at all in the whole file, it is a matter of the export.
How it comes about
- A part made from a template in which a material was never set
- A purchased part from a supplier library without material data
- Material filled in only on the drawing, not in the model
- An export that does not include the material properties
03 Approach
Find, fix, prevent.
How to find it
Materials are in the STEP as a property, if the CAD package sends them along. You can put them side by side per part and so see which are missing or have a default value.
- 1 Open the STEP in the free check or convert the BOM to Excel.
- 2 Look at the column with the material per part.
- 3 Search for empty values and for Generic, Default and other default names.
- 4 Put the materials you find next to what is on the drawing and in the BOM.
Fix
- Assign the material in the CAD package, on the part itself, so it works through everywhere.
- Use one spelling per material, for example always S235JR and not also Steel, Mild.
- Then check whether the weight in the BOM has followed.
Prevent
- Put a material in your part template, so empty never occurs.
- Record a list of permitted materials and check against it automatically.
- Include material in your release check, next to dimensions and revision.
With BOMproof
Every release, without having to think about it.
BOMproof puts your STEP model, your PDF drawings and your Excel BOM side by side and points out every deviation: with a pin in the 3D model and a balloon on the drawing. You tick off what is correct.
04 Frequently asked questions
No or default material.
01 Why does my model say Generic?
That is the default some CAD packages fill in as long as you do not choose a material. The model does calculate with it, with a general density, so the weight seems right while the material is not fixed.
02 My STEP contains no materials at all. Is that bad?
Not every package writes materials into the STEP. Then you cannot check the model on it and the drawing and the BOM remain the source. In BOMproof those two are then put against each other.
03 Can I check that only permitted materials are used?
Yes, in BOMproof you record in a requirement set which materials are allowed. Every part with a material is held against it, and every rule gets an outcome.
05 Often seen together
Other errors from the same corner.
You never want to hunt for this error by hand again.
Upload your model, your drawings and your BOM and let BOMproof check them against each other. Book a demo with your own design.