Using this Course

This course will take the user through the entire cove.tool process and equip them with the knowledge to operate the fastest and most precise early stage building performance tool on the market. As an automated building consultant, cove.tool is designed to work with the entire team and integrate itself throughout the entire design process.

As the user progresses through this course, each section will dig deeper into the concepts of BPA (Building Performance Analysis) and BEM (Building Energy Modeling) workflows, and the course enrollees should gain a general understanding of cove.tool’s methods and radical transformation of the traditional workflows. 

Who is this course for?

Anyone in the Architectural, Engineering and Construction (AEC) industry. The users represent the leading AEC firms and comprise of Architects, Engineers, Contractors and Owner. 

What do the users get for signing-up?

Throughout this course the users will receive an all-inclusive access to various articles, diagrams, reports, and video tutorials. Also, new users will receive a 15 day full-access trial to test and explore what cove.tool has to offer.

What is cove.tool?

Cove.tool is the automated building performance platform that parametrically optimizes design options for energy and cost performance in the early stages of the building design process. Validated results, unique features, and a robust web application interface give every project team the edge to make the best decisions sooner and more often. Fully enabled with plugins to Revit, Sketchup and Rhino, cove.tool makes it easier for design teams to meet their 2030 targets, LEED, energy codes and more.

cove.tool is redefining energy modeling and parametric optimization by building smarter, more accurate models in a tenth of the time. Using automation for tedious tasks cuts time and cost, leaving the creative part to you. We learn everything about your project’s sustainability goals so the custom cove.tool results can help you meet your targets. In just a few minutes, you will have a professional energy model and report for your project.  


When would I use cove.tool?

Cove.tool is an early stage building performance tool - this means it is best utilized in pursuit, concept design, schematic design and design development. The graph below showcases the significant cost savings to the projects when performance decisions are shifted to the earlier stage of design. As seen in the graph, the cost of making design changes rises as we move to later design stages, while the cost impact of design changes is minimal in early stages. This allows design teams to move away from the traditional process of completing energy modeling and other performance modeling in the construction drawing phase only to get compliance. At that point, the software serves as a simple check instead of truly allowing for data driven design decisions, leading to sub-optimal and expensive solutions. 



Case Studies

Public Safety Facility – Georgia Institute of Technology

Published on March 19, 2019 ​ Architect: Houser Walker Architecture, Pond Landscape Designer: Pond MEP Engineers: Pond Contractor: Ajax Sustainability Consultants: Pattern r+d 01//... Read More

High Performance Student Union

Published on February 11, 2019 Architect: Workshop Architects, Cooper Carry Landscape Designer: Olin MEP Engineers: Newcomb and Boyd Contractor: Gilbane​... Read More

Energy Efficient Classroom using cove.tool

Published on January 28, 2019 ​​ Image Courtesy Cooper Carry 01// Project Profile The classroom building is located in Saint... Read More

12 Reasons to Upgrade the Workflow with cove.tool

  1. Allows for a parametric cost vs energy optimization, to find the most cost optimal way to get to an energy target.
  2. Has automated inputs for all energy codes across United States and Canada, to ensure the energy model is accurate and realistic. The user can model projects across the globe in cove.tool. 
  3. Allows for easy geometry imports, with limited/no prep to the existing 3D models done by architects.
  4. The only energy modeling software that supports Revit, Sketchup and Rhinoceros/Grasshopper
  5. Allows for quick façade guidance and strategy comparison for energy and daylight
  6. Is recognized by the AIA 2030 and helps track and report the firmwide performance in real time.
  7. Creates automated reports with climate data, benchmarks, energy analysis and parametric optimization.
  8. Creates significant time savings in the workflow. It takes less than 30 minutes of training to get started with a model and less than 10 minutes to complete your first model.
  9. Has detailed validation (including ASHRAE 140) and case studies to highlight the accuracy of all the results.
  10. Calculates the potential LEED points and payback based on your design and the energy cost of the project's location.
  11. Allows for integrative design process with the ability to invite consultants to collaborate on projects in cove.tool
  12. World-class user support to resolve all questions in less than 24 hours

Creating a project in cove.tool

Getting Started

Getting started with automated energy modeling is easy. The user can begin by entering their profile details to experience the cove.tool customization. Selecting the project role sets the level of detail that the user must go through to get the energy model. The architect mode is the most automated and the engineering mode is the least automated. Cove.tool also uses information about the user’s experience and the size of the firm to provide the right type of documents, tutorials, and other helpful materials upfront.  

cove.tool is a web-based application whose entire process is hosted and computed in the cloud. A user with cove.tool would only need internet access for the application and not be required to install any local software. Cove.tool takes advantage of the cloud to do more than free up space on the desktop. It also allows users a number of features including: data back-ups so the user never loses any work done online, automated updates so the user always has the latest bug-free version, unfettered storage and project creation capabilities, super-fast energy performance results, latest product costs and performance values, and high-resolution diagrams and reports the user can download, and virtual access anywhere, at any time, on any machine.

Another feature on the login page is the blue chat box in the bottom right-hand corner of the screen. This icon is a space for open dialogue that connects the user directly to cove.tool’s technical team. Users are encouraged to use this chat box to look up helpful documents, ask questions about the tool or analysis method, and inform the cove.tool team of any specific issues that are encountered. Tech support and direct communication with the team is available Mon-Fri 8:30-5:30PM EST at no additional cost, and outside of these hours, the dialogue box can be used to provide the highest recommended articles, tutorials, and links to assist you as best it can before the teams return the next workday.


Interface Overview

Once the user is logged in to cove.tool, the top right of the screen showcases the firm’s AIA 2030 performance and lists the project breakdown. With cove.tool as one of the accepted software by AIA 2030 DDX, firms can track all their projects in real time and avoid traditional excel sheet based tracking. This format includes the firm’s total project count, total floor area, projects which currently meet energy targets, and projects on the path to meet the 2030 energy reduction goal. Find out more about the AIA 2030 Challenge here

Beyond the AIA 2030 section, and before entering the project list, the users tab should be clearly visible. The Users Tab is only visible in administrator accounts and is used to set up the company’s users, outside collaborators, and project assignment.

The Users Tab is created to manage multi-user accounts and control who works on what project. This tab will list every unique email currently holding an account with cove.tool at the user’s firm, and emails of users who have been invited to collaborate on certain projects. This Users Tab list is broken into three sections: Invitations, Users, and Collaborators. The Invitations category are pending cove.tool users who have received an outgoing invitation to collaborate on a project. Once the invitation has been accepted, names in the Invitations Category will move to the Collaborator category. Collaborators are account holders from outside the firm who require project assignments from administrators to view/edit projects. These are typically consultants on the projects. The Users Category is a list of all cove.tool users at the firm. They have their own project list and can easily view and collaborate with other users to co-create and manage all firm projects. All accounts can be restricted and/or deleted from the team by right clicking the user’s name and selecting either option.

Returning to the project page will direct the user to the project list. The project list is as the title suggests, a collection of all cove.tool projects that have been created by the user and their firm. Each project in the list will consist of a project summary and various commands to edit, delete, duplicate, or download a report of the project. One crucial feature to highlight is the copy tool which allows users to duplicate pre-existing projects with already defined inputs. This is great for firms who want to explore design options but not change any of the engineering systems, or vice-versa explore the same building design and explore different system setpoints and combinations. The project list also allows users to find a project through a search bar, start a new project with “start new project” button, and see the progress and performance of every project at their firm.


Project Information

To create a project, click the “start new project” button. This page, known as the Project Details page, requires users to input basic building information, which will become useful in automating the inputs of later sections. After adding an image, name, and number to the project, the user will be asked to select a building type from a list of predefined types. Each building type has a pre-defined set of inputs and best practice options integrated into its profile which are the industry standards set up by CBECS, ASHRAE and more. Along with other rudimentary inputs from this and the following page, together they will be used to generate the whole building baseline performance case as well as autofill various inputs in later categories. For modeling a mixed use project, cove.tool allows for up to 3 building types to be selected.

Next is selecting a location for the proposed project. The correct weather file is automatically selected based on the provided location, so entering a specific address is best. Energy Code inputs are rigorously tested for each building type, climate zone, and code version for maximum accuracy. The standard buildings are based on ASHRAE 90.1, ASHRAE 62.1, California Title 24, NECB and Department of Energy’s PNNL standard building prototypes and engineering best practice for accurate, repeatable results. Likewise, specifying location is used to auto-fill inputs of later sections. Project location is also used to generate the climate analysis report. This allows the cove.tool database of energy codes to be properly assigned to the user’s project. If it is a mixed-use building, click each use type that most closely matches the project.

Geometry can be entered manually (when a project is a hand sketch) or uploaded via the Autodesk Revit, Rhinoceros/Grasshopper, or Sketchup plugins. When entering manually, the geometry is broken down into 8 cardinal directions in the interface for easy manipulation of glazing percentages. The software also includes a rotate button, which shifts your value at 45-degree intervals, allowing users to experiment with orientation and learn its impact on energy performance. 

The specific Revit, Rhinoceros/Grasshopper, Sketchup plugin can be accessed by clicking here

Once the Geometry is ready, next set the façade overhangs, fins, and average angle to the horizon. Here users can explore shading strategies and impact of context on their designs. The distance is measured from the center of glass to the overhang and fin, not the top or side of the window. 



Understanding the Energy Use Results

Cove.tool shows efficiency ratings for various project inputs. Having these 3 key features 
1) A color coded rating system
2) Help text directly identifying possibilities for improvement
3) Real time side-by-side inputs and results display for quick energy conservation measure analysis. 
Users can quickly get the hang of how different factors integrate to build the project’s performance profile and what aspects of the building design will need to be modified for a high performance building.

The baseline energy page shows the energy modeling results. In this page, a user can see how the project’s EUI (energy use intensity) compares to the 2030 challenge. Users can also check if the project is achieving any LEED points for energy. Additionally, the software analysis can help the team with the Integrative Process credit in LEED v4. Cove.tool also conducts a utility cost analysis based on the state’s published energy costs along with the energy breakdown.

At the top of the page the user can generate a report to share the results with colleagues, consultants, or even the owner. There are some general weather diagrams along with some conclusions about the project.


Understanding the Water Use Results

impact of low flow fixtures and potential number of LEED points it can yield. Water Use Intensity (WUI) expressed in gallons per square foot per year (gal/ft²/year), is used to determine how much water the building will require during the years of occupation. This calculation is only done for interior water use and uses baseline and WaterSense values for the 5 standard water fixtures as specified in LEED’s Indoor Water Use Category. Cove.tool uses the low and high-performance values multiplied by square footage of the project to produce a preliminary Water Use Intensity (WUI) and possible Water Use Intensity (WUI) Percent Reduction.

Along with calculating Water Use Intensity (WUI), the water use page in cove.tool also calculates a preliminary LEED point summary. As this tool only compares a two performance rates, low [baseline] performance and high [WaterSense fixtures] performance, there are only two possible performance outcomes. Either all fixtures meet baseline performance standards and the project earns 0 LEED points because it was not able reduce on baseline performance, or all fixtures are WaterSense labeled and offer a 37.45% water use reduction from baseline and thus earning 3 LEED points for the project. Another feature cove.tool offers as part of the water use page is the Interior Water Use Breakdown Graph. This graph demonstrates which of the five fixture categories (showers, toilets, urinals, kitchens, and lavatories) dominate the building’s water use based on building type and area. This information is best used in every phase of design when selecting fixtures and is crucial to conserving energy and water use, thus resulting in a better performing building.


Understanding the Climate Results

The Climate Analysis Section is about knowing the user’s building environment and finding out which passive design strategies are best for the project. Architects who understand the passive impacts of climate will be better able to deliver cost effective, energy efficient, buildings. Designing with passive strategies is about understanding the constraints and creating design responses that do not require active mechanical systems. Examples include using ambient energy sources to cool, heat, shade, or ventilate a building space. The challenge with designing for passive strategies is that they must be incorporated in the early stages of the process if they are to be effective. Cove.tool generates 6 Climate Analysis/ Passive Strategy Diagrams, each accompanied with a help diagram to breakdown and package the benefits and disadvantages of various design strategies for the project location.

The cove.tool button creates a downloadable and shareable pdf report of the building performance analysis for the user's project. 



Running the Optimization

Cove.tool’s holistic cost vs energy optimization optimizes not just for energy, but also cost of construction. The results can then be parsed by multiple different metrics like LEED Points, Payback Years, Construction Cost, EUI and more. Some older software packages optimize by component. The only problem is that this means every time a decision is made it eliminates all the other possibilities. This is a classic decision tree problem. This is why cove.tool runs a full building simulation of bundles of components together to ensure that the best combinations are taken into account. 

With just 16 decisions with 3 options per decision a user can quickly have a design space with thousands of possible solutions (3,360 permutations). No person can look through all that complexity, so cove.tool picks the top 100 options for energy and cost and allows the users to look through

An interactive parallel coordinates plot graph is used for searching through the design space to find other bundles that meet the design objectives of the user. This graph is one of the most powerful aspects and can look through the entire design space. Hold down on the mouse to select a portion of the options on each vertical axis and double click to reset an axis. Many owners are willing to pay thousands of dollars to have this kind of analysis run throughout the project to ensure that they are getting the best building for the cost.

Once a user has investigated the range of options presented, the options studied can be modified by using the “change options” button. This also becomes crucial if the preselected options in the optimization graph don’t reflect the actual products the user would consider for final implementation. A user can select from the list of following categories to enter, edit, add, and delete option per the user’s preference. Behind the 9 categories, lies every single energy modeling input.

After a user selects the categories to include in optimization (add multiple options for), part 2 is going through each category via separate “manage input” pages. Each Change Options page is formatted to allow users to edit, add, and/or delete input options. Once inside an input page, each page will be broken up into sections which will then list out the current existing options. This page is most useful when design teams invite outside cost estimators to adjust cost inputs by editing these parameters: Product and/or System Type, Performance Value/Efficiency, and Cost.

Once a user has modified the parametric options, the optimization can be re-run to reflect the updated project. Now, the user can save the final report. The pdf report will contain all the information that was generated throughout the cove.tool process. Like the Baseline Report, the final report will have the energy use analysis with 2030 baseline result and targets, the climate analysis and passive strategies, and façade guidance results. In addition to the earlier report, the final report will include the list of input options, number of available bundles, and the finalized cost vs energy analysis (baseline & premium) that was generated on the final optimization page. All results are displayed on a white background as high resolution PNG files and can be saved out and used in the user’s custom project report.  


Using the Revit Plugin



Cove.tool’s modeling software plugins were created to streamline the import of building geometry. With the custom data collector, cove.tool finds your project, collects the geometry, and exports the correct values into the cloud to run a fast and accurate energy analysis. Because the plugin imports geometry data instantaneously, every time the user changes the geometry, the project can be reloaded to see the latest update of the proposed building’s performance. Here is how the user can use Revit to start a cove.tool project.


Selecting the correct objects to import is important. Cove.tool can detect when these objects are and are not in the correct categories for import selection. With the help of the plugin, Cove.tool will accurately import the “wall” data from the wall categorized objects no matter what stage the Revit model is in. Because cove.tool only uses values from objects which directly affect a project’s energy performance (i.e. walls, roof, skylights, floors, and windows) and cuts out miscellaneous objects, it cuts the need for geometry oriented model prep.


The Revit plug-in uses 3D views for its selection and data export process. These steps will not impact the building geometry at all - instead, the Revit plug-in will require edits in viewport settings to make seamless data collections. This process has yet to meet a building large or complex enough that it couldn’t handle, but here are 4 steps the user can take to make sure a geometry import in Revit, from beginning to end, takes 5 minutes or less.


Step1: Cove.tool’s updated Revit plug-in now allows users to auto-generate 5 unique category 3D-Views (Floors, Roofs, Walls, Skylights, and Windows). These views will be the windows during the geometry selection process. As the user updates the project, these viewports will follow suit and throughout the project’s life, the user will be able to go back and forth from Revit and cove.tool to learn about the building’s current energy and overall whole building performance.


Step 2: Enter any of the newly generated views. Once inside, the user should confirm that the objects are visible which need to be included in the export of the titled category. For example, during the Wall category export, the only objects crucial to the energy simulation of this category are opaque envelope objects of similar heat transfer/ insulation properties. So stray objects in the view such as interior walls, doors, fins, cantilevers, and other non-thermal envelope masses should be hidden. This step is also crucial for the windows and floor categories; see the images to the right for how views should look before and after clean up.


Step3: To clear out these stray objects use the “sunglasses” Hide Element tab found at the bottom of the Revit interface. This command will prompt a temporary viewport which will hide unwanted objects in the current 3D-view. If manual selection is taking longer than expected, try the Left Click Select Similar Objects In Viewport option, to select multiple similar property objects to then remove from view. Once complete, Apply Hide/Isolate View and complete this step for all the other applicable export viewports.


Step 4: Now that all the viewports are complete, begin the geometry export process. The user should log in to their cove.tool account to connect the project to the cloud network. Start a new project in cove.tool’s web-application so when the export process in Revit begins, both projects can be linked using the Switch Projects command. After login and switch projects steps, go through each tab/category and select the correct view for each geometry export.


Using the Sketchup Plugin



Like other plug-ins, cove.tool uses 3D model geometry from SketchUp to auto-fill the geometry input page to complete the building’s project profile. Unlike the other plug-ins, the SketchUp plug-in differentiates itself by being the only geometry export process which auto separates the different geometries into cove.tool layers. This step ensures all the object areas are accurately categorized for final calculations.


Step 1: Isolating the geometry that will be used during the export process. No context or extraneous objects should be left in the view. Depending on the user’s preference, there are two options to pursue when setting up a model. First, a user could export the building simple geometry and start a fresh new file with only the building as its content, or one could just hide everything else in view so that only the cove.tool project is left in view.


Step 2: Once the view is clear, the next step is to make sure to match your building ground level to the SketchUp ground plane. Depending on the stage of the model, the complexity of the file may vary. Models that are further developed tend to have various changes such as undulating contoured sites which would cause the model to float in space once the context is hidden or removed. If the model ground doesn’t match project ground this could cause inaccurate calculations once the geometry export process begins. Matching ground planes can be done be switching to a front view, and moving the building to line up with the ground plane (see image above). 

Step 3: To make sure cove.tool’s plug-in can identify each building geometry object, make sure the objects are on the same layer and that the geometry is made up of single surfaces. Objects which belong to groups or blocks will be skipped once the export process begins. The easiest way to make sure the geometry is all single surfaces is to highlight the model, then “explode.” The remaining geometry is ready for the next step.


Step4: Now that the model is ready, it is time to use the plugin. Once the plug-in has been installed and enabled, a new tab entitled “Extensions” will appear. Go ahead and click the tab and continue to select “Create cove.tool layers.” 11 new layers will appear at the bottom of the layers menu. Makes sure all the objects have been sent to their correct category. Misplaced objects can be normally swapped between layers, so make sure this is done before launching cove.tool. Misplaced objects are the #1 cause of inaccuracy in this plugin.


Step 5: The file is now ready for the geometry export. Again in the “Extensions” tab, select “Launch Cove.tool” to open a web-link inside the plug-in. Cove.tool’s login page will appear, as usual log into the account and navigate to the project that needs to be connected to your SketchUp geometry. Inside the plug-in link, the user has the option to either create a new project, or to search through the project list to find the desired project. 

Step 6: The cove.tool project has now been created/selected. Next, the user will navigate to the geometry page to locate a new option at the top of the page and auto-fill the geometry details with the “Sync with SketchUp” button. Click this to see a comprehensive area calculation of the proposed building. If the user finds some of the information inaccurate, it is advised to flip back to SketchUp and double-check the model’s measurements. Likely there might be an object that is not layered properly and has added up to a calculation in the wrong category. Once everything looks good, click continue to save the geometry export and move forward to see how the building performs.


Using the Rhinoceros/Grasshopper Plugin




Cove.tool‘s Rhino/Grasshopper plug-in is the most powerful of all the plug-ins. This walk-through will take the user through the two part process, first setting up the Rhino file and second, completing the geometry export process inside Grasshopper.


Step 1: Set the Rhino units to meters - this will be necessary once inside Grasshopper. This step will not affect the values that are received once inside cove.tool, but when transferring area calculations through the plug-in because Grasshopper’s structure only always accurate exports of objects in meters.


Step 2: Make sure the model is oriented to the correct cardinal directions. The user can check this by viewing the model in the “Top View” to see if the North façade is facing project North (top of the screen). This will be important as data is collected from the plugin and inserted into the correct geometry categories. Correct cardinal positioning is crucial to getting a quick and accurate energy equation for performance simulations.

Step 3: Once the file is ready, the project geometry will also need to be checked for meshes. Cove.tool’s Grasshopper plug-in will only select single surface objects to export area data. In order to convert mesh objects into single surface objects, use the following two commands. First, “MeshToNurb” to create polysurface copies of the mesh geometries and while still highlighted delete the original mesh-objects. Second, use “MergeAllFaces” command to weld many polysurfaces into single-surface objects. Polysurfaces that do not weld into a single surface object can be converted to single surfaces by using the command “Explode”. Blocks will not be read and will need to be converted to surfaces as well.

Step 4: Use the command “Grasshopper” to launch the app, open the file that was downloaded earlier from Food4Rhino. Be careful navigating the file. Cove.tool’s grasshopper file was custom engineered to get the exact values from the project model. The entire process is modeled and several tips are placed around the file to keep the user on track.

Step 5: Inside the Grasshopper file, there are only 3 areas which require the user’s inputs. 
First fill in the login and password panels with the cove.tool account information. This will link the user’s Rhino project to the cove.tool cloud. Make sure to start a new project in the cove.tool web app before continuing. Once logged in, the project list will update to show the user’s cove.tool project history. Using the number that identifies the project which needs to be linked to the project in cove.tool, correct the project selector to connect.

Step 6: The building geometry export process is almost ready to begin. Before doing anything else, right-click the Grasshopper plane and activate the “LockSolver.” LockSolver is a Grasshopper tool which temporarily disables Grasshopper’s Solver - in other words, it freezes Grasshopper’s computing process so any new components, parameters, or inputs added will not run immediately. Grasshopper is infamous for its freezing and crashing, but keeping Lock Solver consistently activated while working and only disabling when the user is ready for the information to update will make the entire process quicker. 

To begin exporting geometry, create Breps (Boundary Representations) for the following pills: roof surfaces, floor surfaces, skylight surfaces, opaque wall surfaces, and window surfaces. Create Breps by double-clicking the Grasshopper plane and typing “Brep”. Each export is unique and the following will explore tips and challenges for each category. Once all Breps are completed and lines connected, disable the LockSolver and jump to the cove.tool web app to see the results.

Step 7: Obtain building height by right-clicking the building height pill and selecting the “Set one Line” prompt. Jumping back to the Rhino model in consideration, begin a line from the lowest point of the model and continue vertically-locked to the highest point in the model. The measurement will be automatically recorded and once the “LockSolver” is disabled, the information will be updated in the cove.tool project summary.

Step 8: Using a new Brep pill, right-click the Brep and select the “Set Multiple Breps” prompt. Back in Rhino, select the single surface objects that best illustrate the combined surface area that covers the project’s entire roof surface area. This includes all areas that are exterior and seal the areas below them - do not include cantilevers as they have no energy impact on a building. Once selected, back in Grasshopper connect the Brep pill to the roof surface pill with a wire to complete the import. 

Step 9: Repeat the same steps in roof surfaces for floor surfaces with a new Brep. It doesn’t matter how the floors (with thickness, or not) are modeled throughout the project, the only surfaces that need to be selected are the planes which best illustrate the combined floor surface area of the entire project. Be wary of selecting multiple surfaces on the same plane, as they may double-log surface areas and will result in unrealistic calculations and results in the customized cove.tool report.

Step 10: Repeat the same steps in roof surfaces for skylight surfaces with a new Brep. Not all projects have skylights, so it is ok to leave this category empty by not creating/connecting a Brep. This may give the user an error prompt in the Grasshopper code, but will not affect the rest of the data exports, so there is no need to worry. Go into the cove.tool web app and manually enter zero in this category.

Step 11: Repeat the same steps in roof surfaces for opaque wall surfaces with a new Brep. Because cove.tool is an early stage energy modeling software, the only data needed from the building geometry are the areas in which Heat Transfer occurs. Thus, when selecting walls for the cove.tool plug-in, only exterior walls should be selected, everything interior is unnecessary for the types of energy analysis and results cove.tool will generate.. The fins or overhangs do not need to be exported as they have their own page in the cove.tool web app which is manually recorded.  

Step 12: Repeat the same steps in roof surfaces for window surfaces with a new Brep. Similar to Opaque wall surfaces, the window surface selection only pertains to areas on the exterior face of the project. Also, mullions would, in theory, be included in the window selection process and not in the wall surface category, however because of their general size they tend to be minimal blips in the energy simulation results especially for an early-stage energy modeling software, therefore are not necessary to export to cove.tool.


Course Completion Self Evaluation