3.6.1: ModelView

The “ModelView”-component of the “Results” subsection controls the general display properties of the structural model (see fig. 3.6.1.1). More specific visual properties that relate to beam and shell elements can be defined with the “BeamView” and “ShellView”-component. The viewing options get stored in the model. Settings of view-components thus stick with the model and remain valid further down the data-stream until changed by another view-component.

When adding a “ModelView” to the definition it is sometimes a good idea to turn off the preview of all other components so that they do not interfere. Clicking on the black menu headings unfolds the “ModelView”-component and unveils widgets for tuning the model display. Each of these will be explained further below. The range and current value of the sliders may be set by double-clicking on their knob.

Fig. 3.6.1.1: Partial view of a model

The “ModelView”-component features five plugs on its left side:

"Model"

Expects the model to be displayed.

"R-Factors"

There exist two options for scaling the deflection output. First there is a slider entitled “Deformation” in the menu “Display Scales” that lets you do quick fine-tuning on the visual output (see below). Second option: the input-plug “R-Factors” which accepts a list of numbers that “ModelView” uses to scale the displacement-output. Its default value is 1.0. Each item in the list applies to a result-case. If the number of items in this list and the number of result-cases do not match then the last number item is copied until there is a one to one correspondence.

This option for scaling displacements can be used in the course of form-finding operations: The “def.Model”-plug at the right side of the “ModelView” (see below) outputs the model with displaced geometry which can be used for further processing. Selecting item “–all–” on the drop-down-list for the selected load case results in a superposition of all load cases with their corresponding scaling factor.

"ResCase"

Lets one select the visible result-case. The value in “ResCase” will be added to the result-case selected in the drop-down-list of “ModelView”. “—all—” at the drop-down-list and “ResCase” set to 0 result in the first result-case to be displayed. If the resulting number is larger than the number of available result-cases the “ModelView” turns red. If the resulting value is smaller than 0 (the default) all result-cases are superimposed. The possibility of using a number-slider for selecting load-cases makes life easier in case that there are many of them.

"Colors"

Color plots for e.g. stresses use a color spectrum from blue to white to red by default. One can customize the color range by handing over a list of RGB-values to the “Colors”-plug. There have to be at least four colors given. The first color is used for values below, the last color for values above the current number range. The remaining colors get distributed over the number range (see fig. 3.6.1.2). The colors are centered on zero if zero is part of the number range. Otherwise the colors spread evenly between lower and upper numerical limit. In case you want to change the coloring defaults, set them in the “karamba.ini”-file. There it is also possible to switch off the centering around zero by setting “center_color_range_on_zero” to false.

"Ids|Breps"

This plug lets one select those parts of a model which shall be displayed. It expects a list of strings or Breps. The default value is an empty string which means that all of the model shall be visible. As one can see in fig. 3.6.1.1 it is possible to input regular expressions. These must start with the character “&” and adhere to the conventions for regular expressions as used in C#. The identifier of each element of the model is compared to each item of the given string list. In case a list entry matches the element identifier the element will be displayed. Fig. 3.6.1.1 contains four examples of “Id” lists: The first would limit visibility to element “A”, the second to element “B”. The third is a regular expression which matches elements “A” or “C”. The fourth matches elements “A” to “C”. Alternatively one can plug closed Breps into the “Ids|Breps”-plug. In that case only those elements get displayed which lie inside one of the volumes with at least one of their end-nodes.

Fig. 3.6.1.2: Color plot of strains with custom color range

There are five output plugs on the "ModelView"-component:

“Model”

Is the model which was fed in on the left side with viewing options attached.

“defMesh”

You can get the mesh of the shells and beam cross sections of the deformed model for further processing. It is a list of meshes with each item corresponding to one shell or beam.

“defAxes"

Delivers the axes of the beams of the deformed structure as interpolated 3rd degree nurb-splines. Use the Length/Subdivision slider to set the number of interpolation points.

"defModel”

When there are results available from a statical calculation, deflections are scaled and added to the node coordinates of the original model so that the "defModel"-output contains the deformed geometry.

The “Display Scales”-submenu

Fig. 3.6.1.3: Local axes of cantilever composed of two beams, reaction force and moment at support

The “Display Scales”-submenu contains check boxes and sliders to enable/disable and scale displacements, reaction forces at supports, load-symbols, support-symbols, local coordinate systems and symbols for joints at the endpoints of elements. The displacement scale influences the display and the output at the "defModel"-plug. It has no effect on stresses, strains, etc.. The colors of the local coordinate axes red, green, blue symbolize the local X-, Y-, and Z-axis.

The “Render Settings”-submenu

The slider entitled “Length/Segment[m]” lets one control the distance at which beam results (displacements, forces, moments, etc.) are plotted (see 3.6.7). It also sets the number of control points that are used for the “defAxes”-output and for displaying.

In some cases the color display of results gets distorted by the presence of stress concentrations or utilization peeks. They make much of the structure look unstrained with some small patches of color where the peeks are. The “Upper Result Threshold”- and “Lower Result Threshold”-sliders let you eliminate these extreme values. In case of the “Upper Result Threshold”-slider a value of x% sets the upper boundary value of the color range in such a way that x% of the actual value range is below. For the lower threshold it is vice versa. Values in the model beyond the given thresholds are given special colors to make them easily recognizable.

By default the result threshold values given above refer to the value range in percent. Sometimes it turns out to be practical to prescribe absolute values as thresholds (e.g. the yield stress of a material). The radio button group “Result Threshold as” can be used to switch between relative and absolute thresholds.

Limiting the value range of utilization values can be confusing: If the result thresholds are given in percent, then setting the lower threshold to zero and the upper to 100 displays the full range of utilization values. If the result thresholds are given as absolute values then a lower threshold of −100 and an upper threshold of 100 limit the color range to the areas where the material resistance is sufficient.

The “Colors”-submenu

Here one can enable the display of element-, cross section- and material-colors. See sections 3.1.6, 3.3.1 or 3.4.1 for how to set them. In order to to visualize the colors enable "Cross section" under "Render Settings" of the "BeamView"- or "ShellView"-component.

The “Tags”-submenu

The “Structure Tags” menu contains checkboxes for adding visual information to parts of the model:

"Node tags"

attaches node-indexes to nodes

"Element tags"

attaches element-indexes to elements

"Element Ids"

displays the element identifiers

"Elements"

if enabled the “defAxes” output-plug emits the axis of the deformed elements as lines and shows them on the Rhino-canvas.

"CroSec names"

displays the name of the cross-section of each element

"Material names"

displays the name of the material of each element

"Eccentricities"

visualizes beam eccentricities as blue lines at the end-points if active.

"Load values"

adds the numerical values of loads or point masses to the corresponding symbols

"NII"

prints the value of second order theory normal forces NIIN^{II} for all elements where it is not equal to zero. For the meaning of NIIN^{II} see section 3.5.2

The “Result-Case”-submenu

The “Result-Case” menu contains a drop-down list from which one can choose the result-case which should be displayed. When used on a model with loads, the result-cases are equivalent to load-cases. After a buckling-modes, eigenmodes or natural frequency calculation the result-cases contain buckling-, eigen- or natural modes respectively.

By default it is set to “—all—” which means that the results of all result-cases are superimposed. Define displacement-factors by feeding a corresponding list of numbers into the “R-Factor” input-plug. The “Result-Case”-selection sets the result-case to be queried for some shell results-components placed further downstream (e.g. “Force Flow Lines on Shells”, “Principal Stress Lines on Shells”, …).