gardening with autodesk® revit®...november 30 – december 3, 2004 las vegas, nevada gardening...

November 30 – December 3, 2004 ◊ Las Vegas, Nevada

Gardening with Autodesk® Revit®

David Driver, president, 4D Architects, Ltd.

BD24-4 Plants complete the rendering. The AccuRender engine of Autodesk Revit provides a sophisticated plant generator that is tucked behind the scenes. This powerful plant editor can be used to generate any type of plant to place in your rendering.

Who Should Attend:

Anyone who wants to render landscapes using Autodesk Revit

Topics Covered

Understanding the Plant Family site components

Creating your own plant types with AccuRender plant editor within Revit

Rendering the landscape: flowers, fruit, branches, leaves, and more

Visual control of plan symbols of plants

Tips and tricks for other landscape types

About the Speaker: David is the principal of 4D Architects Ltd.. During his 20 years of practicing architecture, David has served as architectural project manager and computer manager. His company provides consulting on CAD standards and implementation to architects throughout the U.S. He also offers training on Autodesk® products. David has coauthored Designing Mechanical Systems with Autodesk® Building Systems and is contributing editor to the CDV Revit® Courseware series. David can usually be contacted at the email address: [email protected]

BD24-4 Gardening with Autodesk® Revit®

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Intro/Preface

Welcome to Gardening with Revit

I put this Autodesk University class together to share with you some ideas on the use of plant families in the Revit project. While I am not a landscape architect, I find that just rendering the architecture of a building without the context leaves much to be desired in the way of expression of design intent. Revit gives you several ways of creating the landscape context for the model. In this class I will be primarily focusing on the Revit Planting Families, taking you through creating a couple of families from scratch. I will talk about some other ways to get plantings into the project such as RCP families later. The reason I focus on the Revit plant families is that with a plant family you have 3 options for generating the plant. You can create model geometry, use the Accurender plant library, or use RPC content files as the base for the rendering. I will focus primarily on the Accurender Plant Library and the editor explaining some of the options available you that you can use to create your own vegetation family types. The Accurender procedural plant editor is a powerful tool that will allow you to place two of the same types of trees near each other. If the height of the two trees is different, the procedural trees will have different branching, making a more realistic type of tree. While the procedural Plant Editor is a very sweet tool, it does take a bit to get used to.

Plants in the Revit Environment:

Plant families are considered by Revit to be a site component and are accessed from the site tab of the design bar.

You can also access them using the component tool off the basics toolbar, but then you have to sort through a bunch of things like desks and such.

If you are looking at a toposurface in plan view, when you place a plant, the plant will sit on the toposurface. When moved in plan view, the plant will follow the contours of the toposurface so it does not appear floating or half buried when you do a rendering. If you move plants in an elevation or section view, they will try to stay attached to the surface they were placed on, but you can move them off of it. Use the

button on the


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options bar if you have split up your toposurface and want to anchor the plant to a different toposurface.

If you understand Revit families, the behavior of Plants in the Revit project will be easier to understand.

In plan view, what is seen is the plan view are symbolic lines.

What is seen in elevation and model views are Model lines. This Model lines will not cast shadows with the new 7.0 functionality unless the plant type is created from model geometry.

A note to those of you familiar with Revit Families. The provided plant families use a nested family to create the geometry within the plant .rfa family. I have not found a way to edit this geometry directly. Instead I start with a planting .rft and create my own geometry from there


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Creating a plant from and existing plant type.

Always start with one of the provided pieces of content, when you create a family. If you can get close to what you want, modifying a few parameters and doing a saveas sure beats having to create one from scratch. There are three families

There are three families of plants provided in 7.0. Shrubs, Conifers and Deciduous.

Each of the families has a few different sample types that you can use.

Creating your own types is a fairly easy process. I will create a Lilac bush from the given rhododendron type within the Shrub Family

Import the family Shrub.rfa into a project. It is in the imperial library in the plants folder.

New for 7.0…After you import the family from the library in 7.0 you do not need to place a plant then go through the tedious RC> Properties> edit/new> duplicate any more.

You can just Right click Duplicate on the Rhododendron 8’ in the Project Browser Family Tree. Select Duplicate of this pop up menu. Rename immediately to Lilac 8’ or else right click on Rhododendron 8' 2

And rename this to Lilac 10’

From the same location in the project browser, right click on Lilac 10’ and select Properties to access the type parameters.

The Properties page for a plant is fairly sparse because the real power lies in the plant editor.

While here, change the plant height to 10’.

On the next line down in the Other Category is a Plant Name. This is just a pointer to a plant definition in the Accurender plant library. You have to pick this line, and then pick the browse button at the right end of this line.


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This brings up the Accurender plant library.

Pick Deciduous on the left, and then lilac (light Variety) in the list in the middle.

Accurender plants have seasons and will be twigs in the winter, flower with light foliage in the spring, and then change colors in autumn. You can preview this by dropping down the season above the preview image on the right.

Pick the OK buttons to get back to the project. The Lilac 10’ is now a plant that you can use in your project.

The final plant in the project looks like this: Spring, Late Summer and plan/elevation, section views

Doesn’t this look good in black and white? <g> Ok, that’s the easy solution…


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The previous solution works well if all you are after is a different type within an existing family. This is primarily useful for rendering. When it comes time for CD’s however, the lilac shows up in plan with the same symbol as the Rhododendron. If you are looking for different symbols for different plants, you will need to grow your own…or at least create your own family from scratch. While I don’t want to focus on family creation, as this would take up 30 pages or so, I will however record the steps below, and give some tips and tricks along the way.

The following is from the help file and is a bit confusing.

• Entourage and plant families have a parameter called Rendering Type in the Family Category and Parameters dialog box. The parameter value determines how the family renders in a project view.

• …snip… • If the family category is Planting, the values for Rendering Type are Geometrical, Accurender

Procedural Plants, or Archivision RPC. If you set the value to Accurender Procedural Plants, then Revit adds three parameters to the family types: Plant Trim Height, Plant Name, and Plant Height. When you load the family into a project, Revit then uses Accurender plant material definitions to render the family. If you set the value to Archvision RPC, this changes the category of the Planting family to an RPC family and therefore the family has the RPC filename parameter for its types. You can then set this filename parameter to the desired RPC file name, such as an RPC plant file. When you render the family, Revit uses that RPC content and ignores the family geometry.

• If you set the value to Geometrical for either category, Revit renders the actual family geometry

While this is somewhat true, I don’t really have a clue as to what they are talking about… just start with the proper family. If you have rpc plants, then start with the rpc.rft. If you are making an Accurender plant then read on…

The following lesson will create a mesquite tree that has three sizes as different types within the same family. As you change the size (type) the geometry in plan will change size as well.

Creating your own Revit Plant family

Start with the plant.rft File menu>New>Family

Draw the plan view symbolic lines in the floor plans Ref level.

I find that the new reference lines do not do what I want them to do. However the polar array in the family editor is a fine thing

Before you start drawing linework add several more reference planes to the plant family. The more reference planes you work with, the less the lines will move around on you when you start flexing the model, and the less constraints you will run across.

Behind the Scenes…Sketch lines have something called automatic sketch dimensions. These buggers will throw you for a loop. Essentially these locate the line in space to Revit. Generally the reference planes will be used by the auto sketch dims (not a hard rule). If you only have the default reference planes, then when you change the family type (and values in the parameters) these dims will try to force the lines to stay relative to the reference planes. If you add a couple more ref planes, then as family is flexed, the lines are forced to change less than if there are only two. Theoretically, in 7.0 you can


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use ref lines for the same purpose, but I think the ref Planes work a bit better

Using the symbolic line tool, draw 2 circles.

I just want the branches visible and not the round circles, so I make the symbolic line circles using the <Invisible lines> from the options bar. Symbolic lines will only show in plan views.

Pick each circle and make their dimension permanent so you can assign them the parameters (create new parameters) outDia and halfDia (inner). These will be used for different plant sizes.

These parameters will control the plan symbol branching.

After you create the parameters, set HalfDia to =OutDia * .5 this allows you to change only one parameter to change the size of the plan symbol.

Draw some branching from the center to the inner circle. Use the symbolic lines and the planting line type.

As you add these lines start at the intersection (Macro SI) of the reference linework. Verify the end point highlights the inner circle befor you pick the point with your mouse. This will establish an inherent constraint between the line you are drawing and the circle, allowing the parameters to drive the geometry.


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Prepare to Flex the lines:

Create at least 3 different family types with different values for the outDia parameter. As you toggle between these different family types picking the apply button, the linework will move along the inner and outer circles. You can create all kinds of constraints to make this hard coded, but I find I can usually get it to work with the soft constraints.

I am just making the names to match what will eventually be the height of the tree. For each family I set the outDia parameter to something appropriate for that tree. Usually I want the symbol to be smaller than the actual drip line, so…

for the 10’ OutDia = 5’



I guess for this tree, I could set this to ½ the plant height…

Flex the inner branches by changing the family type to all three different types and picking apply. If you get a constraints error delete the offending line and try again.

Notice in these two captures how the angle between the lines is not constant. This is due to the automatic sketch dimensions tying these lines to the nearest reference plane

Draw in some outer branches and flex after each branch. Yes, flexing each branch takes time, but it is quicker than having to backtrack and redraw them all.

As you add these lines make sure the start point is the endpoint of one of the inner lines. You need to establish this inherent constraint. If you pick the inner circle instead, the outer branch may have a relationship to the line and the circle which will get you in trouble with too many constraints later on. The end point should highlight the outer circle before you pick the point with your mouse. This will establish an inherent constraint between the line you are drawing and the circle, allowing the parameters to drive the geometry.

You need to flex these lines at this point. I have found that sometimes the inherent relationships between the endpoints work and sometimes they do not work and need to be tweeked a bit.

As you are drawing the outer branches, use the endpoint of the inner branches as the start and the near to the outer circle as the end. This will give you the least number of constraint problems. (rather than intersections or near to the inner circle)

Tip: use the Settings>Snaps and clear all but the Endpoint and Nearest as you do this. Hover the cursor and use the Tab key to cycle through the objects under the cursor to select the inner branch if needed

While it would be lovely to be able to group and then radial array these branches, when you put the linework in a group, it breaks the inherent constraints between the end of the

If you are working with a plant family that does not need to change the plan symbol size you can forgo the parameters assigned to the outer circles. At this point you could select the


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lines and the circles that change with the family type.

linework, group the lines, and then use the radial array to finish the plan symbol.

Finish making the plan symbolic lines by repeating over and over the above steps.

Creating the Model Lines:

You have several choices when making the model elements (what will show up in elevation and 3D views. The easiest is just to draw some model lines. You could create model geometry a well if you wished.

The drawback with this is that you will only get one elevation. There are many reasons why you cannot just draw the elevation in the front view and then array and rotate it in 3D. If you do not want parametric height to the model lines you can draw one symbol (using model lines) in the front view, and another is the left or right view. If you want parametric change with type, you must create a nested family. I am providing a sample dataset with the mesquite tree shown in class – you can download the sample dataset from www.davidddriver.com

This plant type uses a nested family. I created the model lines of the elevations as a generic model family. I drew all the linework in the front elevation, setting the same type of parameters that I used in the plant family. I then load this into the plant family, and place it at the origin. Note that all the model lines are set not to show up with a course view level of detail. I can then rotate this one object (the elevation component) without getting any constraint errors.

To make the Elevation Type show up in the Mesquite Plant family type, you select the elevation component and then on the options bar pick the label>add new parameter. This will automatically set the new parameter to family type. I then go back into the plant family properties and set the appropriate elevation size for each plant size I have.

To finish off the plant family, go through the steps from the first exercise to assign the Mesquite plant from the Accurender plant library


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Working with the Accurender Plant Editor.

In addition to all of the previous, you can create your own plants. If you do not see what you want in the plant library you can create your own plant libraries and plants. These plants are the Accurender procedural plants. They are only visible when you render the view.

Rather than take you through step by step how to create your own plant from scratch here are just some notes regarding the plant editor. These are not “formal” or in any way shape or form authorized by Accurender, getting feedback on this stuff is fairly difficult. Instead, this is just The Plant Editor As I Understand It. I will freely admit that I am not a landscape architect, or botanist, but I have spent countless hours with this interface trying to get my desert landscape created as well as doing some very twisted plants requested by my clients.

Revit 7 still uses the Accurender 3 engine. Accurender at the time of this writing is still in Beta for version 4, so if not the next release, then the release after.

The Plant Library and Plant Editor interface: a biology dissection lesson:

You can use any plant as a template for a new plant. Just right click on the plant name and select from the pop up menu New>User Current Plant as Template

Within the Plant editor you can create and edit branches, leaves, flowers and fruits. A plant is generated based on the parameters you give each of these parts. Different plants will have different branch assignments according to their natural branching structure.

These structures can range in complexity from more or less simple (Cedar at left) to fairly complex (Palm Tree at right)

On the first of the edit pages you will get to name your plant and give it a botanical name. There is no link to the Revit family or type, but you can copy and paste if needed.

Also on this page are a Min and Max trunk diameter. This is a fairly important setting. The values are fractions of feet. You will not be able to set a diameter wider than the max setting. In Accurender, this value is used to calculate taper on the trunk as


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well as then the size to the branches that come off of the trunk.

Somehow Revit overrides this value. In Revit you give the type a height. This height overrules the height you see on this page.

At the lower right, you see the approximate resources this tree will take up. It is often a trade off between what you want and the computer resources you are able to sacrifice for a rendering.

The No Medium Level of Detail prevents Accurender from giving a “rough estimate” of the tree when using draft or lower quality render settings. If you render a tree and it looks a bit off, check this setting.

Working in the Branch Editor:

First Branch is the Trunk:

When you select a branch on the left, you can edit it separately.

On the Geometry control of the branch you get control over the branch itself. Branch 0:0 is the base trunk of the tree.

Elongation. This is multiplier applied to the trunk diameter from the base page. This determines the height of the main trunk - If there is no bending applied.

This example (based on the mesquite) is atypical. Because mesquites (and Acacias) are often pruned in the nursery for multiple trunks, this Branch 0:0 will just be a little nubbin at the ground base. The base trunk diameter varies between .102 an .305, so this will only be ¾ of that height. And then it will taper to .25 percent of the trunk value.

Branches use the width of the parent branch where they branch to determine their starting values, so, any branches that come off this compacted “Trunk” will be different sizes


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The segments per branch is for when you apply gnarl (spiral deform) and wiggle (side to side deform)

Branching:

The branching controls the how THIS branch comes out of its parent. For the first branch (0:0) this is a mute point. For branch 1:0 (the second), this has some meaning.

Vertical base and top = what angle should the branch leave the parent branch. Generally the lower limbs are heavier and have dropped from gravity over time so will have a bigger departure angle. Than those limbs at the top. At least when you are talking about those that are leaving the trunk.

Horizontal Increment: how often this branch will appear on the parent.

Patterns: The pattern you choose will determine the effects (if any) the rest of the values on this page have. I would be nice if those that did not apply to a selected pattern grayed out, but this is not the case.

Spiral:The image shows how spiral branches show up on a tree (albeit a small compact one). For the Spiral the main controls are:

Horizontal Increment. In this case horizontal increment controls the rotation around the parent to the next branch.

Spacing – how far from 1 branch to the next


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Whorl: Think of a pine tree…

Horizontal increment is of no use.

Use Braches/whorl to get the number of branches for each right around the tree.

Use spacing to set the distance between the whorls.

Symmetrical and Alternating… Think a spruce or fir bough. These are two of the very basic ways that trees branch. Add a little horizontal increment and you are set to go. Control number of branches with the spacing setting

Other:

Radius sets the size of the branch as it departs from the parent. This is not a 1:1 ratio. Stick with fractions. Bigger for lower branches, less for secondary and tertiary branches. This will affect branch length.

Flare – also affects branch length. Higher numbers will make child branches longer the further up along the branch you go. (Inverted pyramid) Lower numbers will cause further branches to be shorter

Branchless area. Distance from starting point (on parent branch) to first branch (the one you are editing). – again lower branches higher value, less for secondary and tertiary branches.


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Lastly you should apply a material to the trunk for rendering.

You can make materials seasonal if you like so they only show up if the scene is set to a particular season. While not particularly useful for branches, this is nice for leaves and flowers.

Working with the Foliage editor:

The foliage editor works much in the same way as the branch editor. Instead of with a different set of patterns.

Here the length, width and stem length are all feet. Or fractions of feet. The shape settings are Planar


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Ok you get the point. Stem length just sets the leaf image away from the branch by that amount. Height and length or radius will distort the Opacity map to the specified size.

The opacity map is just a black and white bitmap uses to mask whatever material you assign to the leaf on the materials page.

Tips:

The Plant library is a file. By default it is installed to C:\Documents and Settings\All Users\Application Data\Autodesk\Revit 7.0\Rendering\AccuRenderRedist\SUPPORT

As I create plants I keep them in a different folder that will get backed up with the project. Or to a server location where everyone can access those plants