How would you implement an exploded view (part translation) with IxMilia.Step?

[atmike]

Hi there,

Thanks for maintaining this great project! 🙌

I’m working on a .NET-based tool using IxMilia.Step to load STEP files, modify them, and save them back. One feature I’m trying to implement is an exploded view, where each part (solid/body) of the STEP model is translated along a defined axis (e.g., Z+) to make assemblies more readable.

What I’ve done so far
I can successfully load and parse a .stp file using StepFile.Load(...).

I can enumerate StepRepresentationItems from model.Items.

I’ve written code that attempts to apply an offset to each part:

string inputPath = "CB880.014000  1M Unterschnittmesser RE.stp";
string outputPath = Path.Combine(
    Path.GetDirectoryName(inputPath)!,
    Path.GetFileNameWithoutExtension(inputPath) + "_exploid.stp"
);

var model = StepFile.Load(inputPath);

// Attempt to offset parts
int i = 0;
foreach (StepRepresentationItem item in model.Items)
{
    StepLine line = (StepLine)item; // Only works for StepLine as placeholder

    double offset = i++ * 50.0;

    // My idea was to assign a StepAxis2Placement3D to move parts
    var transform = new StepAxis2Placement3D(
        "", 
        new StepCartesianPoint("", 0.0, 0.0, offset),
        new StepDirection("", 0.0, 0.0, 1.0),
        new StepDirection("", 1.0, 0.0, 0.0)
    );

    // But at this point I don’t know how to assign the new transform to the part.
    // There's no MappingTarget property, and no MappedItem abstraction available.

    // So nothing happens to the geometry.
}

model.Save(outputPath);

What’s missing or unclear

• I cannot find an equivalent to MappedItem or similar transformable entity in the IxMilia.Step model.
• There is no way (that I can see) to assign a StepAxis2Placement3D to a geometric item after it’s been loaded.
• I don’t know how to access or modify the placement of existing parts – if they are defined through ShapeRepresentations or ProductDefinitions, it’s unclear how to reach or transform them.

How would you go about implementing an exploded view using IxMilia.Step?
Specifically:

• How can I identify and isolate individual solids/components?
• Is there any way to apply a geometric transformation (e.g. translation)?
• Are there plans to expose transformation-related structures like MappedItem, or is there a workaround?

Thanks again for your great work – any guidance or thoughts would be highly appreciated!

Best regards,
Michael