Anonymous | Login 2020-06-03 04:13 MSK Project: All Projects Community Open CASCADE
 My View | View Issues | Change Log | Roadmap

View Issue Details  Print ]
IDProjectCategoryView StatusDate SubmittedLast Update
0030082Open CASCADE[OCCT] OCCT:Modeling Algorithmspublic2018-08-23 14:572018-09-09 13:05
Reporternbv
Assigned Tobugmaster
PrioritynormalSeverityminor
StatusclosedResolutionfixed
PlatformOSOS Version
Product Version
Target Version[OCCT] 7.4.0Fixed in Version[OCCT] 7.4.0
Summary0030082: Intersection algorithm returns curve with big tolerance value
DescriptionIntersection algorithm returns curve with big tolerance value.

The intersection curve has a bend and it must be bended indeed (see IntCurve.PNG attached picture). Please use "intersect" DRAW-command with not trimmed surfaces to understand such strange behavior. I.e. this bend is happened in the start place where the curve turns.

Please note, that there are no any tangent zones at the end of the curve.

Nevertheless, the intersection algorithm generates points of WLine, which almost uniform distributed in this place. And it is correct behavior of the algorithm because several these points are in the line (in fact).

However, approximation algorithm tries to satisfy the condition with given tangent at the ends of the intersection curve. And in the considered case, this tangent is really directed almost perpendicular to the curve itself (see again the intersection result between two not trimmed surfaces). This is true reason of the bend.

To fix the problem, intersection algorithm must generate of WLine at the end of the curve.
Steps To Reproducebrestore [locate_data_file bug27928_b1.brep] b1
brestore [locate_data_file bug27928_b2.brep] b2
explode b1 f
explode b2 f
don b1_1 b2_2
bopcurves b1_1 b2_2 -2d
#Tolerance Reached=0.0010828835451753697
# 1 curve(s) found.

axo; fit
TagsNo tags attached.
Test case numberbugs/modalg_7/bug30082_1 bugs/modalg_7/bug30082_2
Attached Files IntCurve.PNG (11,030 bytes) 2018-08-23 14:57

Relationships
 child of 0027928 closed bugmaster BOP common produces empty compound