This article describes how the General Intersection Rule works and how you can configure the rule.
This rule is the most popular rule in Solibri, since it can detect the most typical design errors in construction industry, which are causing delays on site installations and also in building costs.
The article covers the following topics:
Tip
To learn more about rules and rulesets in Solibri, take a look at the articles in this section.
Important
Running this rule with the default values doesn't give useful results; this rule must be configured before use.
The general intersection rule can be widely used for checking collisions, intersections and interference. It is very useful in checking design or work status and decreasing human errors during design. This rule can be parameterized to perform checking between different disciplines in several models. The check is based on the geometrical form of the components, and on the way components create unwanted technical problems or duplicate quantities on materials.
The General Intersection Rule allows you to select the detected components based on their data of properties, such as disciplines, location, type, or any detailed property defined by designer. In the filter tables of this rule, you can select the component classes to be included, excluded or ignored in checking. You can also select whether or not a component must have the required properties defined in the filtering conditions.
This rule detects all clashes between components. First, the rule identifies candidates, and then it analyses the clashes using the actual intersection shape. The intersections are classified based on the shape of the bounding box and the volume of the intersection. The rule reports issues only from the intersections which fail the tolerances and intersection type parameters.
In the Intersection Exceptions dialog, you can define the components and intersection types which will be ignored and therefore not included in checking.
In the Parameters view, you can define the parameters for the rule:
Components to Be Checked:
The parameters of this rule include two component tables, Component 1 and Component 2, where you can filter the components. If you want to, for example, detect collisions between walls, you need to insert a wall component in Component 1 and wall in Component 2. You can select properties with specific values to limit the filtering.
Tip
You can save the filter for further use by clicking 
(Save As), or use an already existing filter by clicking 
(Open).
Include Intersections:
Here, you can define what type of intersections you want to detect in checking:
By default, the intersections are classified based on the shape of the bounding box and the volume of the intersection. However, if volume tolerance is used and the volume value is 0, the rule does not create an issue.
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Duplicate:
A duplicate means that the components set in the filters have similar geometry (bounding boxes need to be inside each other) and the volume of Component 1 and Component 2 differs less than 10%. Also, if the actual intersection shape differs less than 2% from the component volume, it is considered to be a duplicate.
This setting will return a critical severity issue (
), since this reveals unnecessary or hidden components in the model.The rule accepts one component, and all the other components with the same construction type (i.e. the duplicates) are automatically rejected.
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Inside (or contains):
A component is inside (or contains) another, when two components with similar geometry (bounding boxes need to be inside each other) are inside each other and the outer volume is bigger that the inner volume.
This setting will return a critical severity issue (
), since this reveals unnecessary components in the model.The component which is inside another is automatically rejected.
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Overlapping:
When components are overlapping, the geometry and volume of that intersecting area is calculated.
Intersection Tolerances:
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Horizontal Tolerance: If the largest horizontal dimension of an intersection is smaller than this value, the intersection does not produce an issue:
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Vertical Tolerance: If the largest vertical dimension of an intersection is smaller than this value, the intersection does not produce an issue:
Use Volume Tolerance: Use volume tolerance to filter our intersection with small volume. Volume calculation is reliable only for solid geometries.
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Volume Tolerance: The intersections with volume smaller than the given value given are accepted. Volume calculation is reliable only for solid geometries:
Ignore Intersections When Intersecting Components Are:
You can select to ignore intersections when components are in the same system (e.g. MEP ducting and piping) or in the same layer and model.
Intersection Exceptions:
In the Intersection Exceptions dialog, you can define the components and intersection types which will be ignored and therefore not included in checking:
To open the Intersection Exceptions dialog, click Exceptions.
When you are checking the intersections between ARC/STR and MEP components, it is possible to list those exceptions where the checking of intersections is considered irrelevant or not required. Typically, these are small pipes, ducts but also air terminals/valves or lighting fixtures that are wall or ceiling mounted on the component surface level.
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A duct or pipe through a wall:
You have to include the components into exceptions in component filters: wall (or other wall kind of a component) vs pipe/duct (or other long component), but the duct or pipe needs to be orthogonal (89 - 90 degree angle) to the wall. This means that all these components will be ignored in this rule.
Minimum Protrusion: This parameter allows you to specify the tolerance of a protrusion for a duct or pipe through the wall on the other side. Using this value, the pipe or duct must protrude on the other side of the wall within the limits of the value so the intersections between the duct or pipe and wall are ignored and no issues are reported in the Results view. If their protrusion exceeds the tolerance value, then they are not ignored, and an issue is created in the Results view about them.
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A duct or pipe through a slab:
You have to include the components into exceptions in component filters: slab (or other slab kind of a component) vs pipe/duct (or other long component), but the duct or pipe needs to be orthogonal (89 - 90 degree angle) to the slab. This means that all these components will be ignored in this rule.
Minimum Protrusion: This parameter allows you to specify the tolerance of protrusion for a duct or pipe through the slab on the other side. Using this value, the pipe or duct must protrude on the other side of the slab within the limits of the value so the intersections between the duct or pipe and slab are ignored and no issues are reported in the Results view. If their protrusion exceeds the tolerance value, then they are not ignored, and an issue is created in the Results view about them.
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A light fixture through a suspended ceiling:
You need to use this option when the lower elevation of the components match. You have to include the components into exceptions in component filters: e.g. light fixture vs suspended ceiling,
Maximum Protrusion: This parameter allows you to specify the tolerance of protrusion for a light fixture below the suspended ceiling or slab. Using this value, the light fixture can protrude below the suspended ceiling or slab within the limits of the value so the intersections between the light fixture and the suspended ceiling or slab are ignored and no issues are reported in the Results view. If their protrusion exceeds the tolerance value i.e. the light fixture protrudes more than the specified value below the suspended ceiling or slab, then they are not ignored, and an issue is created in the Results view about them.
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An Air Terminal which face match the wall face:
Tou need to use this option when the faces of these components match. You have to include the components into exceptions in component filters: e.g. air terminal vs wall.
Maximum Protrusion: This parameter allows you to specify the tolerance of protrusion for an air terminal or valve that matches the face of the wall. Using this value, the air terminal can protrude from the face of the wall within the limits of the value so the intersections between the air terminal and the face of the wall are ignored and no issues are reported in the Results view. If their protrusion exceeds the tolerance value i.e. the air terminal protrudes more than the specified value from the face of the wall, then they are not ignored, and an issue is created in the Results view about them.
The rule results are arranged into six categories, depending on the type of intersection, and the location and type of components:
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Duplicate Components:
This category lists intersections in which the interfering components are identical in shape and volume. This returns critical severity issues (
), for it reports unnecessary components in the model. All duplicate components are rejected automatically. This is done to all the components of the same construction type. -
Components Inside Each Other:
This category lists intersections in which a component (bounding box) is inside another component. This returns critical severity issues (
), for it reports unnecessary components in the model. The component which is inside another component is automatically rejected. This is done to all the components of the same construction type. -
Similar Intersections in Different Floors:
This category lists intersections that have similar occurrences in more than one floor. Identical intersections are grouped into subcategories. When you select the category, you see a group of intersecting components. The subcategories are sorted by decreasing intersection volume.
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Intersecting Components in Different Building Floors:
This category contains intersections in which components in different building floors intersect. The subcategories are sorted by component types and numbers, and the issues are sorted by decreasing intersection volume. Usually intersections in this category are clusters of intersecting components.
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Similar Intersections in One Floor:
This category lists the intersections that occur several times in one floor. When you select a subcategory, you see intersections that have the same shape.
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Intersecting Components:
This category lists the issues that do not fit in the other categories. The issues are sorted by decreasing intersection volume.
Issue Severity:
The rule severities are determined by certain criteria:
Discipline
Component type
Orientation of the intersections, which is detected based geometrical types planar, parallel or angle with ranges of degree: 0-20 degrees is considered parallel and 70-90degrees are considered as perpendicular.
Component size: "Small" means that the smallest dimension is less than 25mm. Oriented bounding box is used (pipe diameter or slab thickness). "Big" means that the smallest dimension is more than 200mm. Oriented bounding box is used (pipe diameter or slab thickness).
In issues with multiple intersecting components, the most severe intersection sets the severity.
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Low severity (
):If the geometric type can be found for both components, if the components are parallel, the components have architectural one or other discipline and both components are small the severity is
If components are perpendicular and both are linear and small severity is
If both components are planar, and architectural, severity is
If both components are planar, linear and architectural, the severity is
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Examples of low severity issues:
Intersections between small pipes
Architectural walls or slabs intersecting walls or slabs
Architectural walls or slabs intersecting MEP components
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Examples of critical severity issues:
Duplicate components
Components inside each other
All intersections with Doors, Windows, Columns or Beams
Severity Parameters:
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To specify the critical and low severities for specific components, open the Severity Parameters view and set the conditions in the filter table. For example, in the image below, it has been defined that all external walls return a critical issue:
Issue severity is determined by the Use Component and Intersection Dimensions to Determine Severities parameter, which is by default toggled ON.
Results:
The rule results are divided into result categories, which are further divided into type, issue and component levels. You can open the sub-level by clicking the arrow on the left:
The category order in the Results view tree is:
Disciplines (only, if several disciplines are selected in parameters)
Component Types or Systems (only, if multiple component types is selected in parameters)
Intersection Types
Construction Types
When MEP systems are checked against other disciplines, the category levels are:
Component type (Wall, Slab)
Intersected component (Slab)
System of intersecting components
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When you select the Type level category, you can see all the components which cut across the intersected component at once.
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When you select the System level category, you can see the intersecting components of one system.
Tip
In the Results view, you can also browse the results as a List hierarchy:
Reported Data:
The General Intersection Rule has a report about intersection volumes. Intersecting components are organized according to their construction types (spaces by space types). Total component volume and total intersection volume (actual value and percentage value compared to total component volume) are reported. The report gives you an overview about how much extra volume there is in the model of each construction type:
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Rule Tools:
The Tools view includes the same table as the report, with a column for decisions added. In the Tools view, you can make a decision for all components in the specified type:
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A gatekeeper rule is actually a ruleset, where typically two (or more) rules are in multiple levels, where the first level works as a parent. The components of the following sub rule are checked based on the results of those self-configuring parent rule.
Tip
For more information on gatekeeper rules, see here.
When the parent rule has two filters, the rule checks those components that are defined in the input filter 1 "Checked components" and against target components. In rule #1, those components can be any non-container type of components. If the sub level rule is also #1 it will accept also non-container type of components from the both filters Component 1 and Component 2. In this type of ruleset it is important to understand the output delivered to sub level rule. Depending on the rules, the required input for component filter has to match with the parent output.
Important
When any parent rule is delivering only passed or failed components to a sub-rule, these components passing or failing the parent rule are only passed to the filter in Component 1 of this sub-rule.
Component 2 in this instance always looks at the whole model and has to be restricted to the elements that need to be checked against the previous rule outcome components.
For example, a parent rule might test for a certain condition, i.e. to identify all pipes that are over a certain size, that are above ceilings. If this parent rule is set to deliver only passed or failed elements to rule #1, Component 1 filter can be set to any component and it will only use the passed or failed pipes from the parent rule. However, if Component 2, is set to Any, it reviews all model components, not just the pipes passed or failed from the parent rule. Therefore, if Component 2 is used in a sub-rule, it needs to be manually configured.
Components of the sub level are set according to sub rule options:
Check all model components, if passed: If this rule is passed - the whole model is checked
Check all model components, if issues: if this rule has any issues - then whole model is checked
Check only the failed components: only those components that have created issues, will be delivered as a output to the sub rules
Check only the passed components: only those components that have no issues, will be delivered as a output to the sub rules.
The self-configurable rule is not returning issues of the first level. The only way to control and test the operability is to use Checked Components view to see checked, passed and failed components. When parametrizing the rule it is important to understand which one of the components are more critical check. If the rule is incorrectly parametrized, the sub rule will disappear from the Checking view.
Example:
This ruleset checks that all the ducts that are among the passed components the intersection checking on a parent rule, are not ø50mm. Sub rule options is set to Check only passed components.
In the parent rule, we check walls of architectural discipline against ducts of MEP disciplines. All the components from Component 1 and Component 2 filters that have passed will be checked in the sub level.
In a sub-rule, we use rule #230 to validate that none of the passed MEP ducts are with dimension size of ø50mm.
This rule will return us all the acceptable ducts as issues.
Note
If the sub rule has two component filters, the passed or failed elements are passed to Component 1 only. Component 2 needs to be manually configured. If you reverse the order of the rules in the example above, only the passed or failed elements will be passed to Component 1 in rule #1. Component 2 needs to be manually configured, for it receives nothing from the parent rule.