版本：9.4.0
模型浮现动画

加载三维模型，实现模型上下浮现动画效果。
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8"/>
    <title>模型浮现动画</title>
    <meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no"/>
    <style>
        body {
            margin: 0;
            padding: 0;
        }

        #map {
            position: absolute;
            top: 0;
            bottom: 0;
            width: 100%;
        }
        .btn-group {
            position: absolute;
            top: 20px;
            left: 20px;
            color: white;
        }
    </style>
    <script src="https://delivery.mapmost.com/cdn/sdk/webgl/v9.4.0/mapmost-webgl-min.js"></script>
</head>
<body>
<div id="map"></div>
<div class="btn-group">
    <button onClick="start(false)">上盖消失</button>
    <button onClick="start(true)">上盖浮现</button>
</div>
<script>
    let map = new mapmost.Map({
        container: 'map',  
        style: "<your style url>", 
        center: [120.74603465203592, 31.30605899929158], 
        zoom: 16.810035105070947, 
        pitch: 59.48725112156901, 
        bearing: -54.10626584095007, 
        userId: '***', // 授权码
        env3D:{
            exposure: 0.9,
        }
    });

    let modelGroup;
    let modelLayer;

    map.on('load', function () {

        let models_obj = ["../example_data/Olympic.glb", "../example_data/OlympicRoof.glb"].map(item => ({
            type: 'glb',
            url: item
        }));

        let options = {
            id: 'model_id',
            type: 'model',
            models: models_obj,
            center: [120.74603465203592, 31.30605899929158, 6.0],
            callback: function (group, layer) {
                modelGroup = group;
                modelLayer = layer;
            }
        };
        map.addLayer(options);
    })

    function start(isShow) {
        if (modelLayer && modelGroup) {
            let model = modelGroup.children[1];
            if (isShow) {
                let from = {
                    height: 100,
                    opacity: 0.0
                }
                let to = {
                    height: 37,
                    opacity: 0.8
                }
                modelLayer.fadeModels(model, from, to, 2000);
            } else {
                let to = {
                    height: 100,
                    opacity: 0.0
                }
                let from = {
                    height: 37,
                    opacity: 0.8
                }
                modelLayer.fadeModels(model, from, to, 2000);
            }
        }
    }
    
</script>
</body>
</html>