FAQS: Modeling

Navigation: How do I navigate or change my view in form·Z?

form·Z offers many different ways to change views. Here is a quick summary:

Preset views: There are 10 preset views available from the View menu, including 3D and projection views. Note that there are keyboard shortcuts for these, which are listed to the right of their name in the menu. Note also that if you have an Arbitrary reference plane active, you will be able to select the 6 standard projection views for this plane from the Plane Projection item.

Saved views: To save a view, simply click in an empty space in the Views palette. To recall this view, click in the column immediately to the left of the name of the view. You can also click on "View Name" near the top of the palette to access the View dialog, and you can double click a view name to edit its parameters.
Scroll wheel: Version 5.0 and later allow you to zoom in or out using the scroll wheel. Version 5.5 and later also allow you to pan by clicking and dragging the scroll wheel.

Set View: The Set View command is the 8th Window tool from the bottom left corner of your project window. Select this tool and click in the screen to orbit around your objects. Note that there are 3 main "modes" for this tool (Center of Interest, Center of Scene, and Click Point on Reference Plane) that you can access by double-clicking on this tool. Note also that if you are in a perspective view, you can zoom in and out along the line of sight by holding down the option key (OS X) or ctrl-shift keys (Windows) while using this tool.

Direct view navigation: Version 5.5 has added many Direct View Navigation commands that allow you to navigate your project by simply holding down modifier keys and clicking in the screen. For example, you can hold down the command key (OS X) or ctrl key (Windows) and left click to zoom in or out, or right click to Set View. You can see a complete listing of these from the Edit / Key Shortcuts / Direct View Navigation, and these are described in more detail, including illustrations in section 3.2.6 of your User's Manual.

Cone of vision: The Edit Cone of Vision command is accessed from the bottom of the Views menu, which activates 4 separate views into your project, including Top, Front, Side, and a 3D view. It also includes a camera which you can manipulate in the first 3 projection views and see the result in the 4th 3D view.

Layers: How do I know the layer my objects are on, or change them to a new layer?

Objects are always drawn on the active layer. You can Query the Attributes of an object to see which layer it is on, or you can also enable the Layer Option: Highlight Picked (from the Options menu / Layers) which will highlight the layer of any selected objects.

Use the Set Layer tool to move objects from one layer to another.

You can also hold down the shift key while changing the visibility of layers to hold the redraw until you release the shift key.

Numeric entry: How do I numerically create or modify objects?

The Prompts palette (at the bottom left portion of the form·Z window) prompts you step by step through graphic and numeric entry. Your numbers will be entered directly in the Prompts palette and will be interpreted in relation to the status of the A, W, or C checkboxes. (A is for Absolute and unchecking this switches to Relative coordinates; W is for World and unchecked switches to Plane coordinates; C is for Cartesian and un-checking this switches to polar coordinates.) If you only want to change one of the parameters, you can tab through the fields so that you only change the one you want, while you leave the others unchanged.

For example, if you want to create a 10' cube with a corner at the origin, check the AWC checkboxes in the Prompts palette, get the Rectangular Base Shape, and the Extrusion modifier. From the Height menu select either 10', or Graphic/Keyed. Type either (0) or (0,0,0) and press the enter or return key to start drawing the cube at the origin. Type (10', 10') or (10', 10', 0) and press enter again. If you selected 10' from the Heights menu, your cube will be generated directly. If you selected Graphic/Keyed, enter (10') and press enter once more.

To move a copy of this cube up exactly 10' (and thus stack one cube directly on top of another) select the Move tool and the Copy mode. Uncheck the A from the Prompts palette and with the Topological Level set to Object, click on the cube. Type (0,0,10') and press enter. You should now have a copy of your cube directly on top of your first cube. Note that you could also do this graphically by enabling the Point Snap, clicking on a bottom corner of the cube, and then clicking on a point above this on the top face of the cube.

Trees: How can I create trees (or other cutouts)?

Find or create an image of a tree (or person or other). Make sure that the image is cropped exactly to the edge of the tree image and that it has a proper Alpha channel.

Import the image as a projection underlay, using the Underlay command from the bottom of the Windows menu.

From a Top view, create a rough trace of the tree using the Vector Line tool, making sure that you do not go inside any portion of the image, and that you do not go outside the image at its extreme top, bottom, right, or left edges. Do not use more points than necessary for greatest efficiency. (This outline will help you identify which tree you are using in Wire Frame and will also generate the shadow outline when using Opaque Shadows, but will not be visible when rendering with RenderZone and Transparencies, and/or transparent shadows.)

Create a surface style that uses the tree Image as a color map, set the Reflection to Constant, and also load this image as a Transparency Map, checking Use Alpha Channel. (Note that this image can be a PSD or TIF image, but JPG does not support an alpha channel.)

Texture map this surface style onto your tracing of the tree, using a Flat map, Lock Size to NONE, Horizontal and Vertical Tiling set to (1, 1) and check Center, Center.

Rotate your tree object so that it is vertical and rotate a copy 90 degrees from top view if desired.

If desired, create a symbol (perhaps snapping to the intersection of the segments at the base of the tree).

Look at the tree symbols that come with form·Z for an example, which are located in the Symbol Libraries or Trees folders of your form·Z DVD.

Working units: How do I change from English to metric units or otherwise customize the numbers in form·Z?

The Working Units command from the Options menu allows you to customize the type and display of numbers in form·Z. You can switch between English and metric units, architectural or decimal display, set the numeric accuracy, and how many decimal places will be displayed. Note that if you always want to use these customized units in your projects, save this in your template file. (See Customization FAQ's for further details and save your preferred settings in your Template File.)

Placing 3D objects: How do I place multiple objects, or control the alignment of my 3D objects when using the Place tool?

The place tool was originally designed to work with surfaces, so it looks at the "first face" of an object to orient this. You can not control the first face directly, but if you draw a 2D surface (ie, rectangle) you can then join your objects to this and as long as you selected the surface first (before joining), it essentially becomes the first face.

Symbols: What are they and how are they used?

Symbols are a method by which groups of modeling objects or drafting elements that need to be repeated in a project are stored in libraries, from which they can be placed as many times as desired. This can be particularly useful for managing items that are used frequently, or when items need to be easily changed from one set of objects to another.

To create a symbol, select the desired geometry and click in the screen with the Create Symbol tool. The position of your click point is very important, as this becomes the "origin" for the symbol. Pick an obvious point, perhaps snapping to the lower left corner of an object. To make changes to a symbol, open the symbol library (ZLB) just as you would a form·Z (FMZ) file. You can then select the desired symbol from the Symbols palette and modify it as you would any other object in form·Z. When you Save your symbol library and return to your project, the changes will be updated automatically. Note that you should avoid adding symbols to a library that is being edited. The symbol library should be first closed, the symbols added, and then the library re-opened, if necessary.

The Symbol Edit tool allows you to change the scale, location, and orientation of your symbols. This can be applied to each symbol individually, or to many symbols simultaneously. In addition, symbols can be changed from one symbol to another, from one level to another, or even from one library to another. This can facilitate changing from one level of detail to another, or from one product line / scheme to another.

Using symbols will also make the size of your file smaller, but it will still require the same memory usage when rendering the file. This is because symbols are exploded internally before they are rendered.

There is effectively no difference between placing a symbol multiple times vs. moving copies of the symbol.

Symbols can also be used similar to x-ref's. Different users can work on different symbol libraries (ZLB's), updating and enhancing the symbols, while another user can manage the "master" form·Z (FMZ) file. Saved changes to the Symbol libraries will not be updated immediately, but they will be updated automatically as soon as the user switches to a different file (or program) and then back the "master" form·Z file.

Another way to use symbols like x-ref's would be to import a DXF or DWG file and create a symbol for each plan / section / elevation for a building. These could then be placed in the master file and could be used to facilitate the construction of a model. If the DXF or DWG file changes, the file could be imported, the symbol updated and, as soon as the user switches to the master file, the plans and elevations will update. See also the DWG import tips for further information.

Symbols: How do I load a symbol library containing symbols with the same names as in my project and get the program to reference the new library instead of the original?

To do this, you should select All Symbols (or at least the ones you want to change), get the Symbol Edit tool, set the options to Edit Simultaneously, and click in the screen. In the Symbol Instance Edit dialog, change the Library from the old one to the new one. Then unload the old library if you like.

Note that you can use the Select By command (from the Edit menu) to select your symbols. (Check: Object Types from the Geometry tab and scroll down near the bottom.) If you option-click (Mac) or ctrl-shift-click (Win) on Symbols... this will bring up a sub-dialog which will allow you to select sets of symbols based on their library, definition name, color display, layer display, detail level, or any combination of the above.

Symbols: How do I modify symbols?

Make a back-up copy of the symbol library in case you make any unwanted changes. If you have opened the Symbol library, close it.

Load the Symbol library into a project and go to the Symbol Library dialog (by selecting Symbol Libraries from the Options menu). Note that you can Save As or Save A Copy As the library from this dialog if you like.

Select the symbol you wish to both keep and modify and click the Duplicate button to make a copy of this particular symbol. Repeat as necessary for any other symbols for which you wish to modify copies and click OK.

Select File / Open, select your Symbol library, and click Open. Select the symbol you wish to modify from the Symbols palette, which you can open from the Palettes menu.

Make any changes you like and click on the next symbol. When prompted, select Save. Note that this will not overwrite your symbol library file until you select Save from the File menu and this Save will be recorded in a temporary version of your library file called Edit_LibX.zlb, which will be created in the same location as your symbol library.

If you have made any changes to the surface style of the symbol and if this surface style also exists in other symbols, you will be asked if you want to change this surface style for All other symbols. If so, click OK. If you only want these surface style changes to be made to this symbol, click Cancel.

Repeat as necessary to modify your additional symbols as you would like. When you are finished, save the symbol library, Close it and return to your form·Z project. You will then be prompted that the library has been updated and it will be reloaded. You will then see any changes that you have made to symbols that have been placed and you may place additional symbols as you like.

Surface styles when transferring objects: Some times they are not what you expected. Why?

If you copy an object from one file to another and the name of the surface style already exists, you will be prompted to choose if you want to use the New surface style (ie, the one currently associated with your objects), the Existing surface style (ie, the one already in the project), or if you want to Add the New surface style (and rename it, keeping the Existing surface style).

The Color Display for your symbols has been set to Object Color or Best Matching Color instead of Definition Color.

You have moved the objects to a layer that is using a Layer Override that forces the object to use a different color.

If none of these is what you are doing, please contact technical support for further investigation.

Picking: How does it work?

Basics: form·Z allows you to select as many objects as you like without needing to hold down the shift key. Re-selecting an object will un-pick it. As with many operations in form·Z, what gets selected depends on the setting of the Topological Level modifier. This is located immediately to the left of the Pick tool. Thus if you set the Topological Level to Object, you will be picking objects. If you set this to the Face level, then you will be picking faces, and if you set this to Group, then you will be picking groups. Note that there are many pick options, including the ability to select objects or faces by clicking on Edges (default), Inside Boundaries, or both.

Frame pick: Frame picking refers to clicking in an empty portion of the window and then dragging the cursor to create a rectangular "frame." By default, any objects that are completely inside this frame will be selected.

Pick crossing: Pick crossing can be used with Frame pick and Lasso pick, and will select any object that is partially contained inside the frame (or lasso) instead of only objects that are completely inside the area.

Lasso pick: Similar to frame picking except that lasso picking allows you to sketch an irregular boundary to select objects instead of using a rectangular frame.

Pick parade: Sometimes it can be difficult to select a specific object if multiple objects occupy similar pixels on screen. Pick parade allows you to "step through" the objects that share the same pick point. To enable pick parade, hold down the shift key while clicking. You will see the segment of the first object highlight and the rest of the object will also change color. If you click again while still holding down the shift key, you will see the next object highlight. Repeat as necessary until the desired object is highlighted. With versions prior to 5, release the shift key and click once more to select the object. With versions after 5, simply release the shift key and your desired object will be selected.

Select By: This is a very powerful selection tool which is available from the Edit menu. It allows the selection by types of objects, object attributes, and more. For example, if you select object types, scroll down and option-click (OS X) or ctrl-shift-click (Windows) on Symbols..., a sub dialog will appear that allows you to select by symbols from specific definitions or specific libraries. Versions 5 and later have also added the ability to create Selection Sets, so you can save and store these for later use. (See section 3.2.4 of your User’s Manual for more details.)

Non-planar surfaces and restoring planarity: I am getting an error about non-planar surfaces. How do I resolve this?

A non-planar surface is essentially a "not flat" surface. If this surface is facetted, it is not properly defined. To understand this better, draw a cube and move one of its top corners up (perpendicular to the XY reference plane). You have now disturbed the planarity of the top face of this cube. There is no flat surface that goes through the points of this top face, or alternately there are an infinite number of warped planes that go through these points. In order to render this surface properly, or more importantly, in order to execute a Boolean operation, the planarity of this surface must be restored.

There are a number of ways you can use to restore the planarity of non-planar surfaces. In the example of the cube above, one way to "fix" the top face would be to insert a segment from the point that you moved to the opposite corner, which will create a ridge on the top of the cube. Alternately, you could insert a segment from the point adjacent to the one you moved to its opposite, which will create a flat portion on the top of the cube which then slopes up to the point that was moved. If you don't care which type of triangulation occurs, you can simply click on the cube (or the top face) with the Triangulate tool. This will automatically identify the non-planar surfaces and triangulate them for you. Note that, if you are going to perform Boolean operations on this object, it is generally best to use the Strict Planarity option.

If you intend to have a flat surface, but for some reason it is no longer flat, and you do not want to Triangulate this surface, you can restore the planarity by "scaling by zero." To illustrate this trick, move one point on the top of a cube straight up to make the top surface non-planar. Then select all the points on the top of the cube (or segments, or face), activate the Non-Uniform Scale tool, snap to one of the points that is at the "right" height (for the Base of Scale) and enter a scale factor of (1, 1, 0.0000000000001). This will effectively restore the planarity of the surface. If your surface is sloping, then you can define an arbitrary plane and un-check the W from the Prompts palette to scale relative to this plane.

Solids from surfaces: I had a solid, but now it has become a surface for some reason. How do I convert it to a solid again?

It is possible that a face has been deleted or, under certain circumstances, a Boolean might not have be able to construct all faces from its operands. If there are not too many missing faces, you can create and insert these missing faces. Here is a little tutorial that will show you how this is done:

Get a New Model and draw a cube.

Select the top face of the cube, press the delete key, and select Delete Topology. This will now open up a hole in the top of the cube. Query the cube to verify that it is now a surface.

Assuming that you do not know where this hole is, go to your Wire Frame Options / Interactive tab and select Show Direction. Now you will see arrows at the top of the cube, indicating that this face is missing. The edges of the missing face need to be at least .25" on screen to have room to show the arrows, so you may need to zoom into different areas on a more complicated object to find them.

Draw in the missing face using the Vector Line tool and the Point snap .

With the Stitch tool, click on your box and then on the surface that you drew. If you did this right, the arrows will go away and your cube will again be solid.

With objects containing several holes, repeat as necessary.

Version 5.0 has added a new Object Doctor tool. If your object is not too poorly structured, the Object Doctor may be able to repair such missing faces for you automatically.

Terrain models: I am getting an error when trying to generate my terrain model. What can I do?

Most contour information imported from AutoCAD (or other such programs) will need to be modified prior to using it to generate a terrain model. This is true for a number of reasons:

Contours are often broken to make room for numbers that indicate the height of the contours. These breaks need to be manually repaired and the lines need to be joined or connected.

Contours drawn in other programs very frequently contain sloppy data, which can cause errors when creating 3D models. Such errors include crossing, or self-crossing contours. Often the contours need to be examined closely to locate these problems.

You can trouble shoot contours that will not generate a terrain model in a number of ways. We would recommend using the methods in the order that they are outlined below. This discussion assumes that you are already familiar with the documentation regarding terrains as outlined in your User's Manual. If you are not, please refer to this information first. Then:

If you are running form·Z 5.0 or later, you can use the Terrain Doctor script. You can download this by going to this link.

If the Terrain Doctor does not identify the cause of the problem for you, proceed to the next step.

From the Wire Frame Options dialog, turn on Show First Point. This will place a small diamond on the first point of each poly-line. Since form·Z requires either closed contours, or contour lines whose endpoints are outside the site, any diamonds you see inside your site boundary that are not associated with closed surfaces indicate a problem. Use the Query tool (or the Select By command) to see if any shapes with diamonds are open and, if so, use the Line Editing tools (from the tool row above the Self-Copy modifier) to fix this. Once you have completed this process, attempt to generate the terrain. If it fails, proceed to the next step.

Visually inspect your contours at close range. To do this, zoom in close in the upper left corner of the site. How close you zoom in depends on how complicated your site is. If your site is relatively simple, zoom in to 1/4 of X and 1/4 of Y (so that you are seeing 1/16th of your total site). Check for crossing or self-intersecting contours. If that quadrant is OK, then click in the scroll bar to page over to the right. Inspect. Page over. When you reach the edge of your site, page down and then page left. . . Repeat as necessary. After you have completed this phase, again attempt to generate your terrain. If you still get errors, proceed to the next step.

To determine which contours are still causing problems, try generating your terrain model with a partial set of contours. Try half of your contours. If this fails, try half of those contours. By a process of elimination, you can determine which contours are not working properly and then you can inspect these contours more closely to determine where they are crossing, open, incomplete, or whatever is causing the problem. Once you have fixed all the problem contours, you should be able to generate your terrain model.

If you have any contours that are causing problems and you have closely inspected them but you cannot find anything wrong with them, you can send them to support@formz.com. (Note that prior to doing this you should have already completed steps 3 through 6.) Once we have examined your file and determined the problem, we can let you know how to correct it so that you can generate your terrain.

Booleans: What is the “Not Well Formed” message, why does it occur, and how to work around it?

First of all, "well formed" indicates that each and every segment of an object has a reversely coincident segment. If you imagine a cube and trace off the top and front faces going the same direction (ie, clockwise), you will find that the segment they share is equal and opposite. If each and every segment of an object has a reversely coincident pair, then the object is "closed" or solid. If an object is not "well formed," then it is not "closed" in 3D, or it is an ill-formed solid. Surface objects, such as rectangles, are expected to be not well formed. See section 4.0.1 of your User's Manual for a further description and illustrations if necessary.

A “Not Well Formed” message can result during the execution of a Boolean operation if the intersection of all surfaces of the operands can not be properly identified. The user should generally cancel this operation and check for the following basic problems. First, query the object and check that the Topology Type is Solid. If the operands are solids, or mixed objects, they should be separated using the Separate tool -- from the tool row to the right of the Booleans. (Such topology could result from imported geometry, or as a result of joining the volumes of objects whose faces overlap, which should be avoided if they will be operands to Boolean operations.) If the operands are solid, also check to verify that there are not any non planar surfaces or negative volumes, which will be displayed in the middle of the Query dialog. Click the Calculate button if necessary and check the Strict Planarity checkbox. If there are non planar surfaces, triangulate the object using the Strict Planarity option. If the volume is negative, use the Reverse Direction tool to make it positive. If you have fixed these problems, most likely the Boolean will now complete properly.

A Boolean operation could also give this error as a result of tolerance inconsistencies, which can occur when a point of one object is neither on the surface of the other object, nor sufficiently far from it, such that the point is determined to be inside the surface when based on one calculation, yet outside when based on another. Tolerance inconsistencies can be caused by nearly coincident points or surfaces (as illustrated in figure 4.17.1.13 of your User's Manual) and they can be generally avoided when one is careful to do “clean” modeling. Tolerance inconsistencies can also be caused by working at very small scales, especially in relation to your Working Units / Numeric Accuracy settings. In this case, simply scaling your objects up (perhaps 1000 times), performing the operation, and then scaling the object back down again can work around this issue.

Failure to complete a Boolean operation can also be caused by bad geometry, such as objects with duplicate points, zero area faces, coincident faces, or self intersecting faces. The Object Doctor can help identify and correct many such problems, but in extreme cases the geometry may need to be manually repaired, or properly reconstructed.

Accepting the result of a not well formed Boolean can be useful for two main reasons: (1) The result can help locate the area of the problem, which can aid in fixing the operands. (2) The result could potentially be repaired so that it is once again well formed. To identify the location of the problem, accept the result and enable Show Direction from the Interactive tab of the Wire Frame Options dialog. Arrows will indicate segments that do not have a "reversely coincident pair" so that you can identify where there are faces missing. Note that you may need to zoom in so that form·Z has enough space to show the arrows, that is, so that your segments occupy at least 1/8" screen space. To repair these holes, use the Vector Line tool and the Point Snap to draw in a new face (with a 1:1 correspondence between all of the points) and then stitch this face into place. Once all of the missing faces are stitched into place, you will again have a well formed solid object. See the “Solids from Surfaces” FAQ for more details.

Snaps: Why can't I snap to my objects anymore?

Both the objects and layers have snap-ability attributes. The corresponding palettes will show a circle icon to the right of the name of the item. If this circle is deselected, the snaps will ignore this object or layer. You can re-enable snaps by simply clicking in the right most column to the right of the name of the item.

Snaps: How to control the depth of snapping?

By default, snaps will snap to the 3D coordinates of the item being snapped. The Snap Options allow you to lock the snapping to the First Point (relative to the Reference Plane) or Project this snap point onto the Reference Plane. This can be set independently for 2D and 3D views.

Cancel: How do I cancel an operation? Can I cancel and resume a rendering later?

Generally, either the esc key or the command + period keys (OS X) or ctrl + period keys (Windows) will stop an operation. Depending on the complexity of the operation to be cancelled, it may cancel immediately or it may take a few moments to cancel. (There is an inherent dilemma with checking to see if a user wants to cancel an operation -- the less you check, the less responsive it is, but the more you check, the more you slow down the operation by checking instead of executing the operation. If you find that a specific operation takes more than a minute to cancel, please send the file along with a description of what you are doing so we can look into this.)

When generating a RenderZone rendering, you can also suspend the rendering (and resume it later) by holding down the shift key in addition to the cancel command. You will be prompted to save this file and you can resume the rendering by simply opening the file that you have saved.

Skinning: I have drawn source and path shapes with which I would like to make a skin object, but I get a message: “The number of points on a source shape that touch a path does not match the number indicated in the dialog. What should I do?

Skinning requires that BOTH source shapes and paths have coincident points (or at least within the tolerance distance). Thus, wherever a source touches a path, there needs to be a point on BOTH the source and path. If you are having trouble with this, try placing the source objects and path objects on separate layers and ghost the source layer. Turn on the Wire Frame option to Show Points and use the Insert Point and Intersection Snap to insert points wherever the objects intersect. Then ghost the paths layer, make the source layer Visible, and repeat. Once you have points on both the source shapes and the paths wherever they intersect, you should be able to properly skin an object. If you are using version 6 or later, you might also want to use the S-Loft tool with the Guide Curves option as this does not require coincident points where the sources and paths touch.

Paste From Modeling: How do I transfer information from modeling to drafting and maintain my layers and dimensions?

In order to transfer information from form·Z 's modeling environment in to the drafting environment, the model should first be opened, the desired view and display mode selected (Wire Frame or Hidden Line). Then a drafting project can be opened or created and the data can be transferred by selecting Paste From Modeling from the Edit menu.
If you select the Paste From Modeling option to Remove Duplicate Lines, then all lines will be placed on the active layer. Thus you should avoid using this option if you wish to keep the lines in drafting on the same layer that they were in modeling.
Also, most objects will be foreshortened in most perspective and axonometric views. Therefore, if they will be dimensioned in drafting, the dimensions will be smaller than the size of the object in modeling. To prevent this from occurring, objects should either be viewed in a projection view (ie, Top, Front, or Side) or in an isometric view.
Objects will also be pasted using the currently active Line Weight and Line Type.