To Mr. Roaman

Dear Roman
It is the first time to write to you and i hope i could find some help
I have one Box shape and a series of Solids stored in TopTools_HSequenceOfShape
Subtracting individual solid from the box is working perfect even it is complicated one but when i am getting the result of subtraction, which is box minus the solid and try to subtract the second one or the subsequents the model is crashing, Can you till me some advices on how to move through this

Roman Lygin's picture

Hello Sail,

The root-cause is likely in peculiarities of the models and/or their positioning relative to each other. It's impossible to give any particular suggestions without the models. As you probably read on this forum, typical issues may include face tangency, coincidences, large tolerances etc.
Off the top of my head, you could try to create a TopoDS_Compound of your shape sequence and cut it at once. However again this might be sensitive to internal geometries.

Hope this helps.
--- - the Open CASCADE blog - CAD Exchanger, your 3D data translator

Sail's picture

Hello Roman
First of all i appriciate your answer and your honesty.
Sometimes the subtraction from a compound leaves me with open solid result.
Basically the question arised here is as follows
How to control the overall tolerance when you are importing geometry into CASCADE system. I am guessing the problem comes from that
Best and thanks

Roman Lygin's picture

Hi Sail,

Regarding the tolerances, I encourage you to read the chapters "Tolerance management" and use of parameters "read.precision.mode", "read.precision.val" and others in IGES and STEP User's Guides.
By default, the importers try to set minimum required tolerance using a value stored in the file as some guidance. However, there is additional control how to impact that - see documentation. However, setting tolerances is very sensitive.

Hope this helps.

Sail's picture

I Appriciate your reply, will read and will inform you if i have any finding