Rooftop Obstructions — How to Add Realistic Objects and Access Structures to Your Design

Summary:

This article walks you through how to add rooftop obstructions to an OpenSolar design so the 3D view matches the roof your customer is standing on. You will learn how to open the Obstructions and Trees tab, place everyday Indian rooftop objects such as water tanks, AC units, and water heaters, add photorealistic objects such as vents, chimneys, and satellite dishes, draw ladders, walkways, and handrails as safe-access runs, resize and set back each object, and check the shading that tall objects cast on your panels.

Rooftop obstructions are available in the design studio on all imagery modes, and are strongly recommended on RCC terrace projects, where tanks, heaters and AC units are almost always present. Objects placed on a design carry through to the 3D view your customer sees in the proposal.

At a glance — the full obstruction list:

Step 1: Open the Design and the Obstructions and Trees Tab

1. Open your project and go to the Design tab to open the design studio.
2. Load your imagery in 3D, or trace your roof in 2D, before you add objects — either way, obstructions need a real facet to sit on, so they land at the correct height.
3. Open the Obstructions and Trees tab in the left-hand menu.
4. Browse the library — Trees, Roof Add-Ons, Structural Elements and Generic Elements all live in this one tab.

Step 2: Understand the Four Object Types

The library holds four kinds of items, and they behave differently.

• Trees are the existing tree species, used for landscaping and shading context (unchanged by this release).
• Roof Add-Ons are objects that belong to the roof — water tanks, AC units, water heaters, vents, chimneys, satellite dishes and skylights. They are project-wide, so they stay in place across every system option you build, and you can place them before or after the panels.
• Structural Elements are ladders, walkways and handrails. These are drawn as runs that follow the panel layout, so they are bound to the system you draw them on. Like annotations, they are not copied into a new system option.
• Generic Elements are plain shapes — cube, sphere, cylinder and so on — for anything on the roof that isn't covered by a specific library object.

Step 3: Add the Water Tank, AC Unit and Water Heater

Water tank, AC / HVAC unit, and water heater are some of the most common obstructions found on Indian RCC rooftops, and these three objects do most of the work on an Indian terrace. A design that shows them reads as the customer's own roof rather than a generic slab.

1. In the Obstructions and trees tab, select Water tank.
2. Drag it onto the roof and drop it where the tank actually sits — usually near the staircase room or a parapet corner.
3. Repeat for AC / HVAC unit and Water heater, matching the real positions on site.
4. Work from your site photos or survey notes so positions and counts match the roof.

Step 4: Add the Photorealistic Roof Objects

The same library carries photorealistic models of the standard roof furniture. Sizes below are the defaults, ordered by how much shade each object casts.

• Turbine vent (whirlybird) — 0.5 m head, approx. 0.45 m tall. High shading impact.
• Chimney — 0.6 × 0.6 m, 0.9 m or taller. High shading impact.
• Satellite dish — 0.6 m dish on a short mast. Low to medium.
• Mast head — 0.04 m, approx. 1.2 m tall. Medium.
• Pipe vents — 0.075 m. Low.
• Skylight — approx. 0.55 × 1.15 m. Minimal.
• Eyebrow vent — approx. 0.45 × 0.2 × 0.05 m. Minimal.
• Fan / power vent — 0.3 m dome, approx. 0.075 m profile. Minimal.

1. Select the object you need from the library.
2. Drag it onto the correct facet. Add-ons are flush-mounted, so they bed into the roof pitch automatically.
3. Prioritise the tall objects first — a turbine vent or chimney changes your shading numbers, while an eyebrow vent mostly changes the picture.

Step 5: Resize, Rotate and Set Back Each Object

1. Click any placed object to open its settings.
2. Adjust Width, Depth and Height to match the unit on site.
3. Set the Rotation so the object faces the way it does on the roof.
4. Set the Setback — the clearance kept between the object and your panels. The setback updates on the canvas in real time as you resize.

Access structures are not decoration. They show the customer and the install crew how the array is reached and serviced, which signals a compliant, maintainable install. Walkway, ladder, and handrail each have their own section below, since each is drawn a little differently.

Step 6: Draw a Walkway

A walkway gives installers and maintenance crews a safe deck to walk along to reach and clean the panels. It can lie flush with the roof, or be raised on automated legs.

1. Select Walkway from the Obstructions and trees tab.
2. Can drag and drop a walkway and then rotate, or edit the dimensions
3. Decide if it should stay flush with the roof or be raised: turn on Elevated to automatically generate legs and a base, raising the walkway to a comfortable access height. This reuses the same automated leg logic as an elevated mounting structure, so the walkway can be raised to sit at the same height as a nearby elevated structure.
4. Choose a surface: FRP grating or solid.
5. Check the Setback — it defaults to 0, since the walkway already provides its own clearance between panel rows.

Step 7: Add a Ladder

A ladder provides vertical access up to an elevated structure, a raised walkway, or the roof itself.

1. Select Ladder from the Obstructions and trees tab.
2. Click the roof, or the base of an elevated structure, to place it — ladders are typically used to reach an elevated structure or a raised walkway on an RCC roof.
3. Set the Height to match how far it needs to reach.
4. Set the Tilt angle so it leans naturally — anywhere between 60° and 80° (default 75°).
5. Set the Rotation to line up with the access point.

Step 8: Draw a Handrail

A handrail guards the edge of a platform or walkway so installers and maintenance crews have a safety rail to work against.

1. Select Handrail from the Obstructions and trees tab.
2. Click point-to-point along the edge that needs guarding — the same click-to-draw interaction as the cable tool.
3. Click “End run” once the path is finished; there is no need to close the loop.
4. Handrails can be placed in two contexts: along the edge of an elevated structure sitting on top of an RCC roof, or directly on a flush-mounted roof, walkway, or roof edge. Draw the run wherever the actual safety edge is.
5. Posts and rails generate automatically at even spacing along the path you drew.

Step 9: Check the Shading From Tall Objects

Tall objects cast a real shade cone onto panels and structures, so the yield reflects what the roof actually does.

1. Click the affected panel array — it highlights in yellow.
2. Select Shading from the left-hand toolbar.
3. Read the Annual Sun Access percentage for that panel group and compare it with the figure before you placed the object.
4. Click through the monthly averages and the hourly grid to see when the object shades the array.
5. If the loss is unacceptable, move the array, move the object if the customer can relocate it, or split the array into a separate panel group.

Common Questions

Which objects should I always add on an Indian RCC roof?

Water tank, AC or HVAC units and water heater, plus a ladder or walkway where access matters. These are the items a homeowner looks for first, and their absence is what makes a design look generic.

My old project still shows the old generic shapes.

Photorealistic models apply to new placements only, per object type. Existing designs keep the shapes they were built with. Place the object again to get the new model.

Do obstructions affect my yield, or are they only visual?

Both, depending on height. Most objects are realism add-ons, but tall ones — water tank, chimney, mast head — cast a shade cone that the shading calculation accounts for.

My walkway is pushing panels further apart than I want.

Check the setback on the walkway. It defaults to 0 because the walkway itself is the clearance. A setback added on top of it will widen the gap.

I copied my system to compare options and the ladder disappeared.

Ladders, walkways and handrails are bound to the system they were drawn on and are not copied into a new system, in the same way annotations are not. Duplicate previous system or Redraw the run on the new system. Roof add-ons such as tanks and vents are project-wide and will carry over.

Can I place an object on legs, or raise it off the roof?

Not in this phase. Roof add-ons are flush-mounted. Elevated structures and walkways have the ability to be elevated and settings available to add legs. 

Sun access dropped a lot after I added a water tank. Is that right?

Probably, if the tank is close to the array and modelled at a realistic height. Open the shading report and click through the hourly grid to see when the shade lands, then decide whether to move the array or reposition the tank.