Create alignments from objects

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Alignments can either be saved under the alignments collection

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or in the sites collection. As part of a site

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alignments are routes laid out in plan only

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that have defined geometry and denote the linear path of a road, railway

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watercourse or other linear feature. We wish to design,

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we going to create a centerline alignment

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for the existing part of Mcallister Boulevard.

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It is displayed in the drawing as an extract attachment of a survey drawing

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on the home ribbon create design panel, click on alignment,

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then create alignment from objects.

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We use this method when we want to create alignments

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based on existing information that we have in a drawing.

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This could be from land survey information

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when we need to extend or redesign an existing road or it could

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be an architect's planning layout that we want to replicate in our design

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zoom to the survey area of mcallister Boulevard

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on the command line, choose X

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ref

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and pick the red center line of the road at the northern end through the X

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ref

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press enter to accept the selection.

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The direction of our alignment is displayed as an arrow on the alignment.

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You can reverse the direction at this point.

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If you need to by entering R on the command line,

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press enter to accept the alignment direction

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in the crate alignment dialogue, enter mcallister existing for the name,

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the alignment type will be set to center line.

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The options here will place the alignment in a separate subfolder in prospector,

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we won't put this in a sight.

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Placing an alignment in a site will allow it to

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subdivide any parcels that are defined in the same site

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set. The alignment style to existing.

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The alignment style controls how the alignment entities are

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displayed such as color line type and line weight,

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choose no labels for the label set.

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As we don't want to display labels on this alignment,

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deselect add curves between tangents.

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This will prevent civil 3D from adding curves automatically

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between the straight segments in our alignment.

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Click OK. To save the alignment,

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we can now see the newly created alignment in model

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space and also under the alignments centerline alignments collection.

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In prospector,

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we can use prospector to select or zoom to the alignment,

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which is useful. When you have a large model,

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you can right click on the alignment in prospector

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and select properties to see information about the alignment.

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In here, we can change its name and style.

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We can set the position of the zero station,

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adjust the station values

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and review the alignment length.

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We can hide parts of the alignment using masking

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other tabs allow us to change how the alignment,

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intersection points are displayed,

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change how tangents and curves are constrained

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and specify design criteria.

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Now plan the drawing to the proposed part of Mcallister Boulevard.

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We're going to convert the white polyline to an alignment.

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Go back to the home ribbon and choose alignment.

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Then choose create alignment from objects

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in the model. Pick the start of the polyline on the left,

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this will set zero station to that end of the alignment.

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Press enter to accept the selection,

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then press enter again

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to accept the alignment direction

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in the crate alignment. Dialogue, change the name to mcallister boulevard.

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You may enter a description for the alignment. If you wish

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change the style to layout,

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set the label set to major minor and geometry points.

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This will label the alignment with dynamic labels,

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showing the station values and marking changes in geometry

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deselect add curves between tangents.

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The polyline we've picked already has curves defined in it.

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So we don't need to add any curves

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click. OK.

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The alignment has been created with the labels we chose at it.

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Notice the warning symbol that indicates the first curve

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may not be tangential to the first tangent.

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This will often be the case when converting poly lines with curves,

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we're now going to create the sycamore heights alignment

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from the home ribbon click alignments then create alignments from objects.

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This time we have individual autocad lines which we're going to select one by one.

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Be sure to pick the first tangent at the start of the line as shown

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when all of the lines have been selected.

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If your alignment direction is pointing in the opposite direction,

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then enter R on the command line to reverse the direction.

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Otherwise press enter

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in the dialogue set the name to Sycamore heights.

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We leave the other settings on their defaults.

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Make sure that add curves between tangents is selected.

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We want civil 3D to automatically place curves between our selected tangents

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set the default radius for these curves to 300 ft and click. OK.

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Our alignment has been created with curves added between all of the tangents.

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Now we'll create woodside view using the same method.

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Again, we have water

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cds that we're going to convert.

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When you select the lines, pick them in turn, starting at the southern end,

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we want this alignment to run from south to north.

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If your alignment direction is north to south,

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then enter R on the command line to reverse the direction.

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Otherwise press enter to accept

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in the crate alignment. Dialogue, change the name to woodside view,

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keep the other settings, but change the default curve radius

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to 180 ft.

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Click. Ok. To save the alignment.

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Finally, we're going to create the center line for existing road Sycamore Street.

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In the survey drawing, we have two yellow lines that represent the road edges.

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We'll use these two lines to find the center line of the road

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from the home ribbon, choose alignment,

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then create best fit alignment.

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A best fit alignment can be created from blocks

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existing lines or poly lines,

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points,

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Cogo points or feature lines.

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Set the input type to autocad entities.

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Civil 3D will analyze the coordinates of the inputs

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to determine the best fit alignment through the points,

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adding curves and spirals as necessary.

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The inputs can be a single path or two paths to find a center line. As in our case,

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click the button for path one entities and select the

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left hand road edge in the drawing and press enter

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repeat for path two,

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selecting the right hand road edge.

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We need to enter some information to guide the alignment creation,

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set the maximum radius for curve detection to 60,000.

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We're choosing a large value to ensure we get curves added and not just tangents,

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we often get a better result. When we also allow spiral curves to be added,

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set the alignment name to sycamore street,

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change the alignment label set to major minor

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H and V geometry points

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at the bottom of the dialogue deselect label offsets.

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We don't want it to add labels of the offsets to the drawing.

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The cocaine

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A report is displayed showing the centerline point list

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together with the offset best fit information at each point.

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You can't adjust anything in this table.

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It's simply providing information about the correlation

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of the points to the calculated alignment.

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The information in the report can be exported as text

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or copied to the clipboard for future reference,

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close the report to accept the alignment.

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The alignment for Sycamore Street has now been added to the drawing and labeled.

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In

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this model. We have created alignments by converting autocad poly lines and lines.