Possible bug: XDE export to STEP - some instance names are lost

[adam-urbanczyk]

Hello,

I'm observing something weird, possibly a bug. With the atached xbf -> step export some instance names are lost. See below.

out.xbf.zip

Importing of the xbf looks fine:

pload ALL
Open out.xbf D
Xdump D

ASSEMBLY COMPOUND 0:1:1:1 "chassis"
        INSTANCE COMPOUND 0:1:1:1:1 (refers to 0:1:1:2) "wheel-axle-front"
        INSTANCE COMPOUND 0:1:1:1:2 (refers to 0:1:1:5) "wheel-axle-rear"

ASSEMBLY COMPOUND 0:1:1:2 "wheel-axle-front"
        INSTANCE COMPOUND 0:1:1:2:1 (refers to 0:1:1:3) "wheel:left"
        INSTANCE COMPOUND 0:1:1:2:2 (refers to 0:1:1:3) "wheel:right"
        INSTANCE COMPOUND 0:1:1:2:3 (refers to 0:1:1:4) "axle"

PART COMPOUND 0:1:1:3 "wheel:left"

PART COMPOUND 0:1:1:4 "axle"

ASSEMBLY COMPOUND 0:1:1:5 "wheel-axle-rear"
        INSTANCE COMPOUND 0:1:1:5:1 (refers to 0:1:1:3) "wheel:left"
        INSTANCE COMPOUND 0:1:1:5:2 (refers to 0:1:1:3) "wheel:right"
        INSTANCE COMPOUND 0:1:1:5:3 (refers to 0:1:1:4) "axle"

INSTANCE COMPOUND 0:1:1:6 (refers to 0:1:1:1) "chassis"


Free Shapes: 1
INSTANCE COMPOUND  0:1:1:6 (refers to 0:1:1:1) "chassis"

Now a roundtrip via step:

WriteStep D draw.step
ReadStep D2 draw.step
Xdump D2

ASSEMBLY COMPOUND 0:1:1:1 "chassis"
        INSTANCE COMPOUND 0:1:1:1:1 (refers to 0:1:1:2) "chassis"

ASSEMBLY COMPOUND 0:1:1:2 "chassis"
        INSTANCE COMPOUND 0:1:1:2:1 (refers to 0:1:1:3) "wheel-axle-front"
        INSTANCE COMPOUND 0:1:1:2:2 (refers to 0:1:1:6) "wheel-axle-rear"

ASSEMBLY COMPOUND 0:1:1:3 "wheel-axle-front"
        INSTANCE SOLID 0:1:1:3:1 (refers to 0:1:1:4) "wheel:left"
        INSTANCE SOLID 0:1:1:3:2 (refers to 0:1:1:4) "wheel:right"
        INSTANCE SOLID 0:1:1:3:3 (refers to 0:1:1:5) "axle"

PART SOLID 0:1:1:4 "wheel:left"

PART SOLID 0:1:1:5 "axle"

ASSEMBLY COMPOUND 0:1:1:6 "wheel-axle-rear"
        INSTANCE SOLID 0:1:1:6:1 (refers to 0:1:1:4) "5"
        INSTANCE SOLID 0:1:1:6:2 (refers to 0:1:1:4) "6"
        INSTANCE SOLID 0:1:1:6:3 (refers to 0:1:1:5) "7"


Free Shapes: 1
ASSEMBLY COMPOUND  0:1:1:1 "chassis"

Note last 3 instances - names are not preserved and replaced with integers.

I can reproduce the same behavior with CAD assistant. What is interesting, I can edit the instance names in CAD assistant and they seem to be exported fine. The obvious delta is that after exporting some instances are converted from compounds to solids.

Does this sound like an expected behavior, or is it some kind of esoteric bug?